United States

Department of

Agriculture

Forest 

Service

Pacific Northwest

Research Station

Resource Bulletin

PNW-RB-263

October 2011

Republic of the Marshall Islands’ 

Forest Resources, 2008

Joseph A. Donnegan, Steven T. Trimble, Karness Kusto, 

Olaf Kuegler, and Bruce A. Hiserote

Majuro

Atoll Arno Atoll

Mili Atoll

Jaluit Atoll

Ebon Atoll

Ailinglaplap

Taongi Atoll

Namorik Atoll

Wotje Atoll

Wotho Atoll

Bikini Atoll

Kwajalein Atoll

Aur Atoll

Utirik Atoll

Rongelap Atoll

Mejit Island

Maloelap Atoll

Namu Atoll

Lae Atoll

Enewetak Atoll

Ujelang Atoll

Lib Island

Likiep Atoll

AIluk Atoll

Jemo Island

Kili Island

Erikub Atoll

Jabwot Island

Ujae Atoll

Rongerik Atoll

Taka Atoll

Bikar Atoll

Alinginae Atoll
Authors

Joseph A. Donnegan is an ecologist, Steven T. Trimble is an ecologist, Olaf 

Kuegler is a statistician, and Bruce A. Hiserote is an information management 

specialist, U.S. Department of Agriculture, Forest Service, Pacific Northwest 

Research Station, Forestry Sciences Laboratory, 620 SW Main Street, Suite 400, 

Portland, OR 97205-3028. Karness Kusto is the Chief Forester for the Republic 

of the Marshall Islands, Ministry of Resources and Development, P.O. Box 1727, 

Majuro, MH 96960.

Cover: photographs by Steven Trimble.

The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of 

multiple use management of the Nation’s forest resources for sustained yields of wood, 

water, forage, wildlife, and recreation. Through forestry research, cooperation with the 

States and private forest owners, and management of the National Forests and National 

Grasslands, it strives—as directed by Congress—to provide increasingly greater service 

to a growing Nation.

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activities on the basis of race, color, national origin, age, disability, and where applicable, 

sex, marital status, familial status, parental status, religion, sexual orientation, genetic 

information, political beliefs, reprisal, or because all or part of an individual’s income 

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program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET 

Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write 

USDA, Director, Office of Civil Rights, 1400 Independence Avenue, SW, Washington, DC 

20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal 

opportunity provider and employer.
Abstract

Donnegan, Joseph A.; Trimble, Steven T.; Kusto, Karness; Kuegler, 

Olaf; Hiserote, Bruce A. 2011. Republic of the Marshall Islands’ forest 

resources, 2008. Resour. Bull. PNW-RB-263. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 29 p.

The Forest Inventory and Analysis program collected, analyzed, and summarized 

field data on 44 forested field plots for the 10 largest atoll groups in the Republic 

of the Marshall Islands (RMI): Ailinglaplap, Arno, Jaluit, Kwajalein, Likiep, 

Majuro, Maloelap, Mili, Rongelap, and Wotje. Estimates of forest area, tree stem 

volume and biomass, the numbers of trees, tree damages, and the distribution of 

tree sizes were summarized for this statistical sample. A variety of tables with 

graphical highlights provide a summary of RMI’s forest resources and a comparison to prior vegetation mapping and inventory work.

Keywords: RMI, Ailinglaplap, Arno, Jaluit, Kwajalein, Likiep, Majuro, 

Maloelap, Mili, Rongelap, Wotje, biomass, damage, Forest Inventory and 

Analysis (FIA), forest inventory, volume, land cover.
Summary 

In 2008, the Forest Inventory and Analysis (FIA) program conducted a systematic 

inventory for the forests of the Republic of the Marshall Islands (RMI), including 

Ailinglaplap, Arno, Jaluit, Kwajalein, Likiep, Majuro, Maloelap, Mili, Rongelap, 

and Wotje. We estimated forest area, tree stem volume, biomass, carbon storage, 

tree damages, and the composition and percentage cover of understory vegetation species. Forty-four permanent field plots were installed in a variety of forest 

types. In partnership with the Pacific Southwest Region’s Remote Sensing Lab, we 

acquired high-resolution satellite imagery and their staff mapped land cover into 

five broad classes: forest, nonforest vegetation, urban, barren, and inland water. 

Our estimates for this inventory are derived from a sample based on 33,212 acres 

on the 10 largest atoll groups in the RMI (74 percent of the total land area). Forest, 

including agroforest and coconut plantations, covers about 70 percent of the RMI. 

About 12 percent of the landscape was classified as urban land. We estimated gross 

tree stem volume to be about 56 million cubic feet for all size classes including 

seedlings and saplings. Aboveground dry biomass for tree stems 5 inches and 

greater was estimated to be about 854,000 tons. About 37 percent of the trees 

sampled in the inventory had some form of damage. Damage by insects was the 

most prevalent damage agent, with damage by other vegetation following in prevalence. The most frequently identified damage types were damaged foliage, vines in 

the crown, and discoloration of foliage. The RMI’s forests are characterized by a 

unique bimodal distribution of tree diameters owing to the dominance of coconut 

plantation combined with regeneration of other species. Species diversity is somewhat low compared to other Pacific Island groups. A total of 17 tree species and 45 

understory species were measured on the FIA plots. The average number of tree 

species per one-sixth-acre plot was four. The Chief Forester for the RMI Ministry 

of Resources and Development partnered with FIA for planning and data collection, 

and was especially helpful with species identification in the field, knowledge of the 

landscape, and assistance with private and communal land access.
1

Republic of the Marshall Islands’ Forest Resources, 2008

Introduction

This report on the forest resources of the 10 largest atoll groups of the Republic 

of the Marshall Islands (RMI) (fig. 1) was based on a cooperative forest inventory 

conducted in 2008 by the U.S. Department of Agriculture Forest Service, Pacific 

Northwest Forest Inventory and Analysis (FIA) program1 and the RMI Ministry 

of Resources and Development. This work is an adaptation of the national FIA 

inventory system and was tailored to help answer local, national, and international 

questions about the status and trends in tropical forested ecosystems. Our partnership has concentrated on sharing technical forestry skills among cultures and 

agencies. The fieldwork for this inventory was conducted by a multinational crew 

including RMI foresters and mainland U.S. foresters and ecologists.

Through the FIA-RMI partnership, we conducted a sample-based field 

inventory for forested lands in the RMI and provided support to create maps 

that estimate land cover and area. We provide information on understory species 

composition, detailed tree size distribution, biomass, carbon mass, and damages for 

living and dead trees by species. The inventory was designed to provide resource 

managers with a broad overview of the current situation so they can better manage 

their forested and nonforested lands, and manage or mitigate any changes in the 

resource. The summarization of the field data is intended to help managers plan 

sustainable land use practices, plan sustainable supplies of wood, control invasive 

species, control erosion, as well as manage disturbances such as fire, and mitigate 

damages caused by humans and other animals.

Objectives

The objectives of this inventory are to:

• Estimate the current area of forest land by forest type group and stand 

size class.

• Estimate tree volume, biomass, and carbon storage by species and 

diameter class.

• Estimate the numbers of trees affected by damaging agents, such as 

insects and diseases, and estimate the numbers of dead trees.

• Share measurement and analysis techniques among groups involved 

in the inventory.

1 The Forest Inventory and Analysis program is now part of the Resource Monitoring and 

Assessment program of the Pacific Northwest Research Station.
2

RESOURCE BULLETIN PNW-RB-263

Methods

Site Description

The RMI is an independent nation located in the northwestern Pacific Ocean. It 

comprises two primary atoll chains, the Ratak (sunrise) and Ralik (sunset) chains. 

Twenty-nine atolls and five islands or table reefs are spread out across 750,000 

square miles of ocean. The RMI and the United States signed a Compact of Free 

Association2 in 1986 and regularly enter into resource conservation and sustainability partnerships.

Figure 1—The Republic of the Marshall Islands spans an oceanic area of 750,000 mi2 in the northwestern Pacific Ocean. The Forest 

Inventory and Analysis program collected data on the 10 largest atoll groups within the dashed line on the map: Ailinglaplap, Arno, 

Jaluit, Kwajalein, Likiep, Majuro, Maloelap, Mili, Rongelap, and Wotje.

2 The Compact of Free Association grants the RMI sovereignty in domestic and foreign 

affairs and assistance implementing a variety of social, economic, and environmental 

programs, while granting the United States defense rights in the islands.

Bikini Atoll

Ujae Atoll

Wotho Atoll

Majuro

Atoll

Arno Atoll

Mili Atoll

Jaluit Atoll

Ebon Atoll

Ailinglaplap

Taongi Atoll

Wotje Atoll

Kwajalein Atoll

Rongelap Atoll

Maloelap Atoll

Enewetak Atoll

Ujelang Atoll Likiep Atoll

Bikar Atoll

0 50 100 200 300 Miles

Marshall Islands

400 o

Australia

Indonesia

New 

Zealand

Philippines Marshall

Islands
3

Republic of the Marshall Islands’ Forest Resources, 2008

This forest inventory is based on data from 44 permanent field plots and covers 

the 10 largest atoll groups in the RMI (Ailinglaplap, Arno, Jaluit, Kwajalein, Likiep, 

Majuro, Maloelap, Mili, Rongelap, and Wotje), making up about 33,212 acres (74 

percent) of the total land area. The atoll groups are made up of small, narrow, 

and often long islets strung together along coral reef. Each islet is generally less 

than a half mile in width and ranges in length from less than a half mile to several 

miles long (fig. 2). On average, elevations are only 3 to 6 feet above sea level with 

maximum elevations reaching about 15 to 20 feet on dunes and cobble or boulder 

accumulations.

Figure 2—The northeast corner of Majuro is characterized by a mixture of urban and agroforest lands. The islets are narrow and range 

from very short to long, typical of the atolls throughout the Marshall Islands.

0 625 1,250 2,500

Feet o
4

RESOURCE BULLETIN PNW-RB-263

Across over 700 miles north to south in the RMI, a strong climatic gradient 

exists with Hadley-cell precipitation influences: moist and warm equatorial air rises 

over the southern atolls. The moisture in the air condenses and drops as rainfall in 

the south and then the air spreads out in the upper atmosphere where it descends 

as dry air over the northern atolls. This convective cycle is also responsible for the 

increase in trade winds moving from south to north in the Marshall Islands. In the 

southern atolls, precipitation amounts are higher, and average temperatures generally are warmer with greater seasonal consistency than in the northernmost atolls 

(figs. 3 and 4) (Western Regional Climate Center 2009).

Figure 3—Precipitation increases from north to south (Enen Kio, Enewetak, Kwajalein, Ailinglaplap, to Majuro) in the Marshall Islands 

(Western Regional Climate Center 2009).

The Marshall Islands are distant from the main typhoon track in the western 

Pacific Ocean and rarely experience severe typhoons. However, occasional storm 

surges have been known to wash across low-lying islands, wiping out vegetation 

and structures. Changes in sea level and the frequency of coastal surges has become 

an immediate concern for Pacific Island inhabitants, with food and water security 

topping the list of issues.

16

14

12

10

8

6

4

2

0

Precipitation (inches)

Month

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

Average rainfall

Enen Kio

Enewetak

Kwajalein

Ailinglapalap

Majuro
5

Republic of the Marshall Islands’ Forest Resources, 2008

Figure 4—The northern islands (not mapped or inventoried) of Enen Kio (Wake Island) and 

Enewetak show a more seasonal pattern of mean monthly temperature in comparison to the 

southern islands of Kwajalein and Majuro. No temperature data are available for Ailinglaplap 

(Western Regional Climate Center 2009).

76

77

78

79

80

81

82

83

84

Monthly mean temperature (°F)

Month

Jan.

Feb.

March

April

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

Enen Kio

Enewetak

Kwajalein

Majuro

The soils in the Marshall Islands are calcareous sand and tend to be well-drained 

fine sand to coarse cobble (Laird 1989). The soils are generally poor in nutrients 

and of low moisture holding capacity but are the plant’s source for nearly all water 

and nutrients absorbed through the roots (Deenik and Yost 2006). Soils under some 

interior vegetation are underlain by phosphitic hardpans from accumulations of bird 

droppings (Fosberg 1954, Mueller-Dombois and Fosberg 1998). Organic soils also 

are found in the limited mangrove areas and in areas where soils have been amended 

for growing food crops like taro.

Vegetation Types

The native forests of the Marshall Islands have largerly been replaced by agroforest, especially coconut plantations (fig. 5). Native vegetation remains in some of the 

undisturbed atolls, commonly a mixed-broadleaf forest, Neisosperma forest, Pisonia 

grandis forest, Tournefortia argentea forest, and Pemphis acidula forest (MuellerDombois and Fosberg 1998) (see table 1 for scientific and common names of trees).
6

Table 1—Scientific names, common names,a estimated number and gross volume, and standard errors for estimated tota

measured as trees in the Marshall Islands

Estimated Standard 

number error for Gross volum

Number	 (≥ 1 inch	 estimated (≥ 5 inches

Scientific name	 Common names	 measured	 diameter)	 number (±)	 diameter) Allophylus timorensis (DC.) Bl. kutaak 8 183,520 136,009 63,860 Artocarpus altilis (Park.) Fosb. ma 5 16,780 8,531 727,825 

Artocarpus mariannensis Trec. Marianas breadfruit 6 20,055 20,055 671,271 

Bruguiera gymnorrhiza (L.) Lam. jon, jong 28 369,029 272,531 2,513,566 

Cocos nucifera L. ni, nimaro, nimir, nimur, niram, 465 1,692,388 237,650 36,735,968 

nirik, niwinmej, jiwollab

Cordia subcordata Lam. kono 32 112,021 86,817 1,062,305 Guettarda speciosa L. bwikow utlomar, utilomar, 141 1,795,278 551,157 3,080,481 

wut, wutilomar

Intsia bijuga (Colebr.) O. Ktze. kubok, kubuk 5 18,623 14,523 131,331 

Morinda citrifolia L. nen, nin 37 1,415,394 552,008 30,417 Neisosperma oppositifolia kish par, kojbar 66 765,015 424,609 1,318,141 

(Lam.) Fosb. & Sachet

Pandanus tectorius Park. bob, bop, mwajaal 176 728,697 198,914 3,355,805 

Pemphis acidula Forst. kone, jungi 22 106,646 72,052 536,011 

Pisonia grandis R. Br. kanae, kanal, kangae, knagal 66 573,757 364,842 2,812,103 

Premna serratifolia L. kaar, kar 14 318,318 198,604 88,243 

Scaevola taccada (Gaertn.) Roxb. konnat, kunat, mar kinat 80 4,113,344 1,338,238 35,598 

Terminalia samoensis Rech. ekkon, ekun, kiking, kokon, 9 38,636 23,442 128,244 

kukung, kung

Tournefortia argentea L. f. kiden, kirin 27 162,463 95,537 1,398,956 

 Total 1,187 12,429,963 2,050,217 54,690,124 

a Common names follow Falanruw et al. (1990).
7

Republic of the Marshall Islands’ Forest Resources, 2008

The vegetation types described below use the FIA field plots as the basis for 

classification. Forest types were identified in the field trying to capture the dominant types that encompassed field plots.

Lowland mixed tropical forest—

Field crews found the following tree species (in descending order of abundance by 

forest type, as is the case for all types in this section) in interior forests on RMI 

atolls: Morinda citrifolia, Cocos nucifera, Neisosperma oppositifolia, Guettarda 

speciosa, Scaevola taccada, Pandanus tectorius, Pisonia grandis, Bruguiera 

gymnorrhiza, Tournefortia argentea, Allophylus timorensis, Premna serratifolia, 

Artocarpus mariannensis, Intsia bijuga, Cordia subcordata, Artocarpus altilis, 

and Terminalia samoensis.

Figure 5—Coconut plantations are abundant throughout the Marshall Islands and have replaced the majority of native forest vegetation.

Steven T. Trimble
8

RESOURCE BULLETIN PNW-RB-263

Strand or halophytic vegetation—

Dominant species found on FIA plots here include Scaevola taccada, Guettarda 

speciosa, Pisonia grandis, Cocos nucifera, Pemphis acidula, Cordia subcordata, 

Pandanus tectorius, Tournefortia argentea, Terminalia samoensis, and Intsia bijuga.

Mangrove forest—

Mangroves occur in limited areas around the margins of some atolls in the RMI. 

Although limited in extent, combined with the shallow reef system, they help to 

buffer storms, preserve the coastline, and offer wood and food resources. Dominant 

species found within this type were Bruguiera gymnorrhiza and Cocos nucifera.

Agroforest—

Typical agroforest in the tropical Pacific is characterized by an abundance of fruit 

and nut trees interspersed with other canopy species. Agroforest tends to occur 

within and near settlements. In the Marshall Islands, coconut plantations dominate 

the agroforest areas. Some of the most common species found in this type include 

Cocos nucifera, Morinda citrifolia, Guettarda speciosa, Premna serratifolia, 

Allophylus timorensis, Pandanus tectorius, Pisonia grandis, Terminalia samoensis, 

Tournefortia argentea, Cordia subcordata, Artocarpus altilis, and Scaevola 

taccada.

Inventory Methods

The RMI inventory was based on the FIA inventory design that was implemented 

across the mainland United States beginning in 2000. Adaptations were made to the 

national design to include additional branching and rooting forms, additional tree 

crown measurements, and special-interest species ranging from invasive plants to 

pathogens to culturally or economically important species of various life forms. In 

the mainland FIA program, plots are spaced within forest land on a 3.3-mile grid. 

With the assistance of the RMI Ministry of Resources and Development, plots were 

distributed at approximately 12 times the spatial intensity of the mainland inventory 

plot grid.

The FIA plot cluster is composed of four 24-foot-radius subplots (fig. 6). Three 

of those subplots are equally spaced, as if on spokes of a wheel, around the central 

subplot. The distance from the middle of the central subplot to the middle of each 

subplot on the three spokes is 120 feet.

A variety of information was collected at the plot, subplot, and tree levels 

(USDA FS 2005). Differences in forest-type conditions are also mapped. For 

example, roads that intersect subplots are mapped, as are clear boundaries in 

forest tree size classes. The primary variables collected include plot location, 
9

Republic of the Marshall Islands’ Forest Resources, 2008

Forest Inventory and Analysis 

Pacific Islands Plot Design 

N 

Overall plot footprint: ~1.5 acres

Distance between subplot centers: 120 feet

Distance from subplot center to microplot center: 12 feet

1 

2 

4 3 

Plot 

Subplot Microplot 

6.8-foot-radius microplot: 

 seedlings + saplings

Key 

24-foot-radius subplot: 

 all trees (>5 inches 

 diameter at breast height)

Figure 6—The plot design used for the continental U.S. Forest Inventory and Analysis program was adopted with slight simplification 

for the inventory in the Pacific Islands.

slope, aspect, elevation, subplot slope position and shape, tree species, diameters, 

heights, damages, branching and rooting forms, decay, epiphytic loadings, crown 

characteristics, tree locations, and regeneration information. The fieldwork for this 

inventory was performed from February to April 2008.

Analysis Methods

The forest land, volume, biomass, and carbon estimates that FIA derives are based 

on a system that uses aerial photography or satellite imagery to define different 

types of land (strata) across the landscape. The simplest stratification is separating 
10

RESOURCE BULLETIN PNW-RB-263

land into forest and nonforest strata. However, stratifications can be assisted or 

refined by using ancillary data such as topography, soil information, life zone or 

climatically based information, and prior inventories of vegetation groups. Because 

boundaries and research questions often change through time, FIA generally 

chooses to post-stratify the plot sample by using a consistent spatial distribution of 

plots across forested landscapes.

The RMI stratification for estimating numbers of trees, volume, biomass, and 

carbon was conducted via a classification of 2006 QuickBird satellite data. The land 

cover classification divided the landscape into forest, urban, nonforest vegetation, 

barren, and water types. At least 10 percent tree cover was used as the basis for 

the forest-land classification, and includes both agroforests and mangrove forests. 

Nonforest vegetation includes other vegetation types with less than 10 percent tree 

cover. A geographic information system was used to sum acreage for each type. 

The acreage each field plot represented was derived by dividing the total acreage 

of forest by the number of field plots. Adjustments were made for plots that could 

not be visited owing to hazardous conditions or denial of access. The analysis also 

accounted for the linear atoll features via adjustment of expansion factors. Average 

stand size (mean diameters of trees) was expanded from the plots to the landscape 

level by using the same expansion factors. Note that the FIA stratification area differs from that of the area mapped for the vegetation classification.

Wood volume was estimated for individual trees by approximating the centroid 

method (Wood et al. 1990, Yavuz 1999) using tree height and two stem diameter 

measurements. These measurements are expanded to tree-level volume estimates by 

using equations for sections of a cone. Both gross stem volume and net stem volume 

estimates were calculated. Net stem volume subtracts damage and rotten defects 

from gross stem volume. Biomass for individual tree stems was estimated by using 

the specific gravity for known species. For species where specific gravity was not 

known, an average specific gravity of 0.5 grams per cubic centimeter was used. 

These estimates of aboveground tree biomass are derived from bole volume and 

include only biomass for the main stem, excluding branches, roots, and foliage.

Traditional site productivity estimates require forest stand age, derived from 

the annual rings of forest trees. However, tropical trees do not produce consistent 

annual rings. Previously we had used a modified topographic relative moisture 

index (TRMI) (Parker 1982) as a proxy for site productivity in other Pacific Island 

groups. However, because TRMI uses a weighted, additive combination of slope 

steepness, slope shape, and slope position to assess the potential moisture retention 

in a forested stand, we opted not to use the TRMI in the essentially flat atolls of 
11

Republic of the Marshall Islands’ Forest Resources, 2008

Figure 7—Land cover was mapped via a Forest Service partnership with the Pacific Southwest Region’s Remote Sensing Lab by using 

very high resolution 2006 QuickBird satellite data. Image data were obtained through a U.S. Department of Agriculture consortium with 

the Foreign Agriculture Service and the Natural Resources Conservation Service.

0 625 1,250 2,500

Feet

o Land cover

Forest

Nonforest vegetation

Water

Urban

Barren

the Marshall Islands. Remeasurement data from these plots at the next inventory 

cycle will provide an estimate of productivity. Until then, soil mapping and nutrient analyses (Deenik and Yost 2006, Laird 1989) remain the best estimate of site 

productivity for the Marshall Islands.

Forest-type mapping was conducted independently by the Pacific Southwest 

Region’s Remote Sensing Lab (S&PF-RSL) with support from FIA. Land cover 

polygons were generated from QuickBird imagery and labeled with assistance from 

RMI foresters. The 2006 QuickBird satellite imagery was used for the mapping and 

served as the basis for land cover estimates (fig. 7).
12

RESOURCE BULLETIN PNW-RB-263

Figure 8—Seventy percent of the Marshall Islands is estimated to be forested in a 

mixture of agroforest and native species. Urban lands account for 12 percent of the 

land cover.

Reliability of FIA Data

The area of forested land cover classified from the QuickBird satellite imagery was 

assumed to be accurate and used as the basis for the expansion of the numbers of 

trees, tree volume, and tree biomass from the plot to the forest-population scale. 

Possible sources of error not accounted for in our estimates include errors in the 

land cover map owing to incorrect interpretation of the image, errors from rounding when working with pixel-based imagery, and measurement errors on field 

plots. Standard errors for the expansion of our estimates from field plots to the 

forested landscape were calculated according to the proportion of area occupied 

by forest. Forest areas were treated as known rather than estimated, and variance 

was calculated by using methods in Cochran (1977). Using one standard error as 

our basis for evaluation gives a 68 percent chance that the true total gross tree stem 

volume (≥5 inch diameter) for the RMI lies between 47.9 and 61.5 million cubic 

feet. There is a 68 percent chance that the true number of trees (≥1 inch diameter) 

for the RMI lies within the range of 10,379,746 to 14,480,180. Readers are cautioned to examine the standard errors associated with species-level estimates for 

the number of individuals and volume by tree species in table 1.

Resource Highlights

Land Cover

The RMI is currently about 70 percent forested, which includes native, agroforest, 

and coconut plantation forests (fig. 8, table 2). About 12 percent of the landscape 

was classified as urban land including roads, and about 4 percent was classified as 

nonforest vegetation including savanna and agricultural lands. The area used for 

land cover estimates totaled 33,212 acres.

70%

3%

12%

14% <1%

Land cover

Forest/agroforest

Nonforest vegetation

Urban

Barren

Water
13

Republic of the Marshall Islands’ Forest Resources, 2008

Table 2—Estimated area by land cover by island in the Marshall Islands, 2006a

Atoll group

Land cover Ailinglaplap Arno Jaluit Kwajalein Likiep Majuro Maloelap Mili Rongelap Wotje Total

Acres

Forest/agroforest 3,068 3,242 2,699 2,530 2,140 1,196 1,813 2,900 1,567 2,097 23,252

Nonforest vegetation 32 55 48 264 133 56 256 82 131 78 1,134

Urban 156 95 142 1,480 102 1,583 85 124 100 116 3,983

Barren 382 462 434 639 415 343 430 748 514 385 4,751

Water 9 2 3 10 28 1 38 0 92

 Total 3,648 3,856 3,326 4,924 2,790 3,205 2,585 3,892 2,311 2,676 33,212

a Figures for 2006 were summarized from the work of Liu and Fischer (2007), aggregating area totals with a geographic information 

system.

Forest Structure

To capture the predominant diameter of live trees in forest stands, we estimated 

stand size class for forested field plots in the RMI. The dominant size class (60 

percent of acreage) tends to be moderate-sized stands, in the 11- to 19.9-inch diameter category (fig. 9). About 28 percent of acreage in the RMI is made up of stands 

in the 5- to 10.9-inch category, and only about 12 percent of acreage is dominated 

by very small trees in the less-than-5-inches category.

Figure 9—The dominant size class for forested stands tends to reflect the dominance and maturity 

of coconut plantations. Sixty percent of the acreage is characterized by stands in the 11- to 19-9-inch 

diameter category.

12% 

2,765

28% 

6,083 

60% 

13,104 

Acres by stand size class (inches)

<5

5–10.9 

11–19.9 

The diameter distribution for trees in the RMI shows a “reverse-J” distribution, 

demonstrating that regeneration is abundant (fig. 10, table 3). The distribution is 

slightly bimodal showing not only small size classes are well represented, but that 

trees in the 11- to 14.9-inch categories are also well represented. The trees in the 

11- to 14.9-inch category are primarily coconut, representing a cohort of mature 

plantation trees (fig. 11). Coconut is well represented in the larger size classes; 
14

RESOURCE BULLETIN PNW-RB-263

Figure 10—Regeneration of small trees is abundant in the Marshall Islands. Trees in the 11- to 

14.9-inch diameter category are also well represented.

Number of trees by size class

Total trees in all classes: 12,429,963

8

7

6

5

4

3

2

1

0

1.0–2.93.0–4.9

5.0–6.97.0–8.9

9.0–10.9

11.0–12.9

13.0–14.9

15.0–16.9

17.0–18.9

19.0–20.9

21.0–22.923.0–24.9

25.0–26.9

27.0+

Diameter (inches)

Trees (millions)

Figure 11—Coconut (Cocos nucifera) dominates the size class distribution for the moderate-sized 

diameter range. The lack of smaller diameter trees demonstrates that plantations are maturing and 

not being replaced on a large-scale basis.

0

100

200

300

400

500

600

700

Number of trees (thousands)

Diameter (inches)

Cocos nucifera

5.0–6.97.0–8.9

9.0–10.9

11.0–12.9

13.0–14.9

15.0–16.9

17.0–18.9

19.0–20.9

21.0–22.9
15

Table 3—Estimated number of live trees on forest land by species and diameter class

Diameter class (inches)

	 5.0–	 7.0–	 9.0–	 11.0–	 13.0–	 15.0–	 17.0–	 19.0–	 21.0–	 23.0–	 2

Species	 < 5.0	 6.9	 8.9	 10.9	 12.9	 14.9	 16.9	 18.9	 20.9	 22.9	 24.9	 

Number of trees

Allophylus timorensis 169,945 6,821 3,411 3,342 Artocarpus altilis 3,342 3,342 3,342 3,342 3Artocarpus mariannensis 6,685 6,685 3,342 3,342 Bruguiera gymnorrhiza 297,404 10,232 10,232 3,411 10,232 13,643 6,821 3,411 6,821 3,411 3,411 Cocos nucifera 3,411 72,905 284,870 635,763 504,593 133,911 50,183 3,342 3,411 Cordia subcordata 43,944 27,149 17,054 6,821 6,821 6,821 3,411 

Guettarda speciosa 1,384,473 170,377 121,389 58,989 39,904 10,164 5,129 4,854 

Intsia bijuga 3,411 8,391 6,821 

Morinda citrifolia 1,404,293 7,758 3,342 Neisosperma oppositifolia 578,378 104,145 55,274 13,575 3,411 10,232 

Pandanus tectorius 127,459 345,719 200,950 44,338 3,411 6,821 Pemphis acidula 55,472 23,933 7,195 20,046 

Pisonia grandis 379,825 64,735 44,271 27,149 16,985 10,164 10,164 13,643 3,411 

Premna serratifolia 294,853 16,780 6,685 

Scaevola taccada 4,105,088 4,457 3,799 Terminalia samoensis 30,805 4,420 3,411 Tournefortia argentea 69,109 43,412 13,882 8,6 60 5,056 14,726 4,166 3,452 

 Total 8,741,717 940,518 639,591 484,035 745,233 563,947 194,489 70,579 19,183 13,643 10,205 3
16

RESOURCE BULLETIN PNW-RB-263

Wood volume (fig. 13, tables 4, 5, and 6), biomass (fig. 14, table 7), and carbon 

storage (table 8) tend to be concentrated in the medium-sized diameter classes in 

the RMI and reflect the abundance of coconut and the dominant-sized cohort of 

the plantations.

however, sustained copra (the dried meat, or kernel, of the coconut) production may 

require replacement of older senescing trees.

For trees at least 5 inches in diameter, tree heights are predominantly in the 30- 

to 39-foot and 40- to 49-foot height classes (fig. 12). The tallest tree on an FIA plot 

was found on Majuro, a Cocos nucifera that measured 15.6 inches in diameter and 

approximately 105 feet tall. The largest diameter tree was found on Arno, a Pisonia 

grandis measuring 31 inches in diameter and 96 feet tall.

Figure 12—Tree heights are well distributed with heights of 30 to 49 feet dominating forested stands.

<10

10–19

20–29

30–39

40–4950–5960–6970–7980–89

90–99

100 +

Height (feet)

Number of trees (thousands) 

Number of trees 

by height class

(≥5 inches diameter)

1,000

900

800

700

600

500

400

300

200

100

0
17

Republic of the Marshall Islands’ Forest Resources, 2008

5.0–9.9

10.0–14.9

15.0–19.9

20.0–24.9

25.0–29.9

Diameter (inches)

35

30

25

20

15

10

5

0

Gross volume (million cubic feet)

Volume by size class

Total volume in these size classes: 

54,690,124 cubic feet

Figure 13—Wood volume is concentrated in the 10- to 14.9-inch diameter category.

Table 4—Estimated volume of live trees on forest land by diameter class

Diameter class (inches)

< 5	 5–9.9	 10–14.9	 15–19.9	 ≥ 20 All sizes

Cubic feet

Gross volume 1,373,017 9,663,923 31,731,109 10,159,628 3,135,464 56,063,141

Net volume (≥ 5 in) 9,636,236 31,671,365 10,080,721 2,538,794 53,927,117

Table 5—Estimated number of trees per acre, 

basal area per acre, net volume per acre, and 

standard errors (SE) for trees ≥5 inches, 2008

Estimate SE

Trees per acre 168 13

Basal area (square feet per acre) 107 9

Volume (cubic feet per acre) 2,457 242
18

Table 6—Estimated gross volume of all live trees ≥5 inches diameter at breast height on forest land by species and diamet

Diameter class (inches)

Species 5.0–6.9	 7.0–8.9	 9.0–10.9	 11.0–12.9	 13.0–14.9	 15.0–16.9	 17.0–18.9	 19.0–20.9	 21.0–22.9	 23.0–24.9	 25.0–26.

Cubic feet

Allophylus timorensis 18,875 20,871 24,114 Artocarpus altilis 7,042 18,430 127,852 129,564 444,937 Artocarpus mariannensis 61,354 158,223 116,991 334,702 Bruguiera gymnorrhiza 34,464 83,528 29,343 211,853 428,467 309,827 195,026 426,274 424,474 370,309 Cocos nucifera 9,287 483,156 3,521,500 12,185,631 13,287,599 4,832,018 2,136,817 114,147 165,814 

Cordia subcordata 152,351 179,272 149,875 114,925 127,258 189,631 148,992 Guettarda speciosa 621,069 853,340 650,193 559,366 189,064 93,205 114,245 

Intsia bijuga 16,827 41,800 72,704 

Morinda citrifolia 11,246 19,171 Neisosperma oppositifolia 399,051 384,696 150,395 57,523 326,476 Pandanus tectorius 1,386,857 1,284,892 487,695 52,276 144,085 Pemphis acidula 187,221 116,382 44,748 187,659 Pisonia grandis 194,080 254,997 260,312 217,015 259,604 227,980 523,681 192,891 

Premna serratifolia 48,895 39,348 

Scaevola taccada 13,102 22,496 Terminalia samoensis 87,132 19,774 21,338 Tournefortia argentea 219,075 196,724 113,152 119,991 82,319 316,152 211,753 139,790 

Total 3,406,575 4,080,231 5,525,369 13,706,239 14,676,618 6,540,133 2,985,088 866,419 932,171 844,801 444,937 
19

Republic of the Marshall Islands’ Forest Resources, 2008

0 

50 

100 

150 

200 

250 

300 

350 

400 

450 

500 

Biomass by size class

Total biomass in these 

size classes: 854,027

Stem biomass (thousand tons) 

5.0–9.9

10.0–14.915.0–19.9

20.0–24.9

25.0+

Diameter (inches)

Figure 14—The distribution of stem biomass reflects the wood volume dominance in the 10- to 

14.9-inch diameter category.

Table 7—Estimated aboveground dry stem weight of live trees ≥5 inches diameter at breast height on forest 

land by species and diameter class

Diameter class (inches)

5.0–	 7.0–	 9.0–	 11.0–	 13.0–	 15.0–	 17.0–	 19.0–	 21.0–	 23.0–	 25.0–	 27.0–	 	 All

Species 6.9	 8.9	 10.9	 12.9	 14.9	 16.9	 18.9	 20.9	 22.9	 24.9	 26.9	 28.9	 29.0+	 classes

Tons

Allophylus timorensis 295 326 376 997

Artocarpus altilis 110 288 1,995 2,022 6,944 11,360

Artocarpus mariannensis 958 2,469 1,826 5,224 10,477

Bruguiera gymnorrhiza 538 1,304 458 3,306 6,687 4,836 3,044 6,653 6,625 5,780 39,230

Cocos nucifera 145 7,541 54,962 190,187 207,386 75,416 33,350 1,782 2,588 573,357

Cordia subcordata 2,378 2,798 2,339 1,794 1,986 2,960 2,325 16,580

Guettarda speciosa 9,693 13,319 10,148 8,730 2,951 1,455 1,783 48,079

Intsia bijuga 320 796 1,384 2,501

Morinda citrifolia 176 299 475

Neisosperma oppositifolia 6,228 6,004 2,347 898 5,095 20,573

Pandanus tectorius 21,645 20,054 7,612 816 2,249 52,376

Pemphis acidula 2,922 1,816 698 2,929 8,366

Pisonia grandis 3,029 3,980 4,063 3,387 4,052 3,558 8,173 3,011 10,637 43,890

Premna serratifolia 763 614 1,377

Scaevola taccada 204 351 556

Terminalia samoensis 1,360 309 333 2,002

Tournefortia argentea 3,419 3,070 1,766 1,873 1,285 4,934 3,305 2,182 21,834

 Total 53,226 63,826 86,487 213,920 229,065 102,075 46,590 13,523 14,549 13,185 6,944 10,637 854,027
20

RESOURCE BULLETIN PNW-RB-263

Table 8—Estimated carbon mass of live trees ≥5 inches diameter at breast height on forest land by species 

and diameter class

Diameter class (inches)

5.0–	 7.0–	 9.0–	 11.0–	 13.0–	 15.0–	 17.0–	 19.0–	 21.0–	 23.0–	 25.0–	 27.0–	 	 All

Species 6.9	 8.9	 10.9	 12.9	 14.9	 16.9	 18.9	 20.9	 22.9	 24.9	 26.9	 28.9	 29.0+	 classes

Tons

Allophylus timorensis 147 163 188 498

Artocarpus altilis 55 144 998 1,011 3,472 5,680

Artocarpus mariannensis 479 1,235 913 2,612 5,238

Bruguiera gymnorrhiza 269 652 229 1,653 3,344 2,418 1,522 3,327 3,312 2,890 19,615

Cocos nucifera 72 3,770 27,481 95,094 103,693 37,708 16,675 891 1,294 286,678

Cordia subcordata 1,189 1,399 1,170 897 993 1,480 1,163 8,290

Guettarda speciosa 4,847 6,659 5,074 4,365 1,475 727 892 24,039

Intsia bijuga 160 398 692 1,250

Morinda citrifolia 88 150 237

Neisosperma oppositifolia 3,114 3,002 1,174 449 2,548 10,286

Pandanus tectorius 10,823 10,027 3,806 408 1,124 26,188

Pemphis acidula 1,461 908 349 1,464 4,183

Pisonia grandis 1,515 1,990 2,031 1,694 2,026 1,779 4,087 1,505 5,319 21,945

Premna serratifolia 382 307 689

Scaevola taccada 102 176 278

Terminalia samoensis 680 154 167 1,001

Tournefortia argentea 1,710 1,535 883 936 642 2,467 1,652 1,091 10,917

 Total 26,613 31,913 43,243 106,960 114,533 51,038 23,295 6,761 7,274 6,593 3,472 5,319 427,014

Number of Canopy and Understory Species

In addition to counting and measuring overstory trees, understory vegetation 

cover and layer heights were estimated for shrubs, forbs, vines, and grasses on 

FIA subplots where a species occupied at least 3 percent cover on that subplot 

(table 9). Tree seedlings that are less than or equal to 1 inch in diameter are also 

estimated as understory vegetation cover (table 10). Special interest species (e.g., 

rare, endangered, medicinal, or invasive) identified by island foresters were also 

noted when found. However, if a species covered less than 3 percent of a subplot 

and was not listed as special interest, it was not enumerated.

For the 2008 inventory, 24 tree species (including seedlings) and 45 understory species were measured on FIA plots. On a per-plot basis (approximately 

one-sixth acre), the mean number of tree species found was 4 (fig. 15).

Tree Damage and Mortality

We estimated about 37 percent of the individual trees in the RMI show some sign 

of damage (table 11). The most prevalent damage types are damaged foliage, vines 

in crowns, and discolored foliage (fig. 16). For the identifiable damaging agents, 

damage by insects, other vegetation, and weather ranked as the most prevalent 

primary damage agents (fig. 17).
21

Republic of the Marshall Islands’ Forest Resources, 2008

Table 9—Average understory vegetation covera on Forest Inventory and Analysis field subplots by species 

Number of Standard deviation across 

Scientific name	 Cover	 subplots	 subplots where species was found

Percent

Asplenium nidus L. 8.7 44 8.1

Bidens pilosa L. 10.6 7 7.2

Boerhavia tetrandra G. Forst. 1.1 8 0.4

Bothriochloa bladhii (Retz.) S.T. Blake 10.0 1

Caesalpinna bonduc (L.) Roxb. 1.0 1

Canavalia cathartica Thouars 10.2 25 8.6

Cassytha filiformis L. 9.8 36 9.7

Centella asiatica (L.) Urb. 2.5 4 0.6

Chamaesyce prostrata (Aiton) Small 1.0 2 0

Clerodendrum inerme (L.) Gaertn. 3.5 4 4.4

Conyza canadensis (L.) Cronquist 4.9 7 6.7

Cordyline fruticosa (L.) A. Chev 1.0 1

Crinum asiaticum L. 3.0 1

Digitaria setigera Roth ex Roem. & Schult. 1.5 4 0.6

Dodonaea viscosa (L.) Jacq. 6.0 7 4.7

Eleusine indica (Linnaeus) Gaertn. 7.2 5 5.2

Epipremnum pinnatum (L.) Engl. 1.0 1

Eragrostis amabilis (L.) Wight & Arn. ex Nees 2.0 1

Euphorbia cyathophora Murray 1.0 1

Eustachys petraea (Sw.) Desv. 7.4 12 9.3

Fimbristylis cymosa R. Br. 3.3 29 3.0

Hedyotis sp. L. 3.0 1

Hemigraphis reptans (G. Forst.) T. Anderson ex Hemsl. 23.3 3 14.4

Ipomoea sp. L. 3.0 1

Ipomoea violacea L. 10.5 23 14.6

Lepturus repens (G. Forst.) R. Br. 5.1 28 6.5

Nephrolepis acutifolia (Desv.) Christ 3.2 14 2.7

Nephrolepis hirsutula (J.R. Forst.) K. Presl 6.4 10 3.3

Oldenlandia biflora L. 2.0 2 1.4

Osmorhiza mexicana Griseb. ssp. bipatriata 2.0 1

(Constance & Shan) Lowry & A.G. Jones

Paspalum setaceum Michx. 6.1 8 5.0

Phyllanthus amarus Schumach. & Thonn. 2.0 1

Phymatosorus grossus (Langsd. & Fisch.) Brownlie 3.2 78 2.7

Portulaca lutea Sol. ex G. Forst. 3.0 2 0.0

Soulamea amara Lam. 21.6 5 18.2

Sphagneticola trilobata (L.) Pruski 4.0 3 1.0

Tacca leontopetaloides (L.) Kuntze 2.4 10 1.2

Thuarea involuta (G. Forst.) R. Br. ex Roem. & Schult. 6.0 17 7.7

Triumfetta procumbens G. Forst. 2.3 15 1.4

Turnera ulmifolia L. 1.0 1

Unknown annual grass 1 1.0 4 0

Unknown forb 3.0 5 1.2

Unknown perrenial grass 1 3.1 11 2.9

Vigna marina (Burm.) Merrill 13.6 20 14.4

Wollastonia biflora (L.) Dc. 10.7 40 13.9

a Percentage cover of “1” indicates cover less than or equal to 1 percent. Cover estimates are averaged among subplots where each species was found. 

A total of 135 subplots were surveyed for vegetation cover. The number of subplots where a species was found and the standard deviation for cover 

estimates provide an idea of spatial variability for each species across the island group.
22

RESOURCE BULLETIN PNW-RB-263

Table 10—Average understory tree covera on Forest Inventory and Analysis field subplots by species

Standard deviation 

Number of across subplots 

Scientific name	 Common name	 Cover	 subplots	 where species was found

Percent

Aidia cochinchinensis Lour. randia 3.0 2 0

Allophylus timorensis kutaak 3.1 9 1.8

Artocarpus altilis ma 1.0 1

Artocarpus mariannensis Marianas breadfruit 3.0 1

Barringtonia asiatica (L.) Kurz wop 1.0 1

Bruguiera gymnorrhiza jon, jong 35.0 4 17.8

Calophyllum inophyllum L. luech, luwej 1.0 1

Cocos nucifera ni, nimaro, nimir, nimur, niram, nirik, 13.0 114 14.2

niwinmej, jiwollab

Cordia subcordata kono 2.0 4 1.4

Erythrina variegata (L.) Merr. coral tree, tiger claw 5.0 1

Guettarda speciosa bwikow utlomar, utilomar, 2.3 42 1.7 wut, wutilomar

Intsia bijuga kubok, kubuk 2.0 2 1.4

Morinda citrifolia nen, nin 3.0 53 3.9

Musa spp. L. kebran, banana 1.0 1

Neisosperma oppositifolia kish par, kojbar 13.3 11 18.0

Pandanus tectorius bob, bop, mwajaal 4.6 72 5.5

Pipturus argenteus (Forst. f.) Wedd. arame, arme 2.0 2 1.4

Pisonia grandis kanae, kanal, kangae, kangal 3.6 7 3.1

Premna serratifolia kaar, kar 3.3 9 2.7

Scaevola taccada konnat, kunat, mar kinat 5.4 36 5.8

Suriana maritima L. kalane, newe, ngiangi, niani, kekun, 8.0 1

rekung

Terminalia samoensis ekkon, ekun, kiking, kokon, kukung, 2.2 13 1.2

kung

Tournefortia argentea kiden, kirin 10.0 1

a Percentage cover of “1” indicates cover less than or equal to 1 percent. Cover estimates are averaged among subplots where each species was found. 

A total of 135 subplots were surveyed for vegetation cover. The number of subplots where a species was found and the standard deviation for cover 

estimates provide an idea of spatial variability for each species across the island group.

Figure 15—Relative to other Pacific Island groups, the number of tree species per one-sixth-acre plot 

is somewhat low, averaging about four tree species per plot in the Marshall Islands. The small size 

of the islets and great distance from larger land masses reduces the probability for colonization with 

new species.

0

5

10

15

20

25

1–2 3–4 5–6 7–8

Number of plots

Number of tree species on Forest Inventory and Analysis plots
23

Republic of the Marshall Islands’ Forest Resources, 2008

Table 11—Number of trees by primary damage type and species for all trees

	 Broken	 Broken	 Broken	 	 Cracks/	 Damaged

Species	 No damage	 bole	 or dead	 roots	 Conks	 seams	 foliage/shoots

Number of trees

Allophylus timorensis 134,212 3,411 3,411 42,486

Artocarpus altilis 10,027 3,411

Artocarpus mariannensis 20,055

Bruguiera gymnorrhiza 338,332 6,821

Cocos nucifera 1,587,366 16,849 6,753

Cordia subcordata 29,232

Guettarda speciosa 735,767 87,465 32,175 2,859 648,930

Intsia bijuga 8,391 3,411 3,411

Morinda citrifolia 777,936 41,636

Neisosperma oppositifolia 681,869 10,232

Pandanus tectorius 671,471 3,411 10,232

Pemphis acidula 70,577 5,974

Pisonia grandis 68,512 86,614 3,411

Premna serratifolia 134,212 180,764

Scaevola taccada 2,509,228 1,292,549

Terminalia samoensis 8,250

Tournefortia argentea 107,786 3,411 21,677 8,158

 Total 7,893,223 94,286 1,013,291 106,874 49,308 30,635 2,135,818

Loss of apical	 Open	 Vines in	 Canker/	 Discolored	 	 All

Species dominance wounds crown gall foliage Other damages

Number of trees

Allophylus timorensis 49,308

Artocarpus altilis 3,342 6,753

Artocarpus mariannensis

Bruguiera gymnorrhiza 6,821 17,054 30,696

Cocos nucifera 25,208 3,411 30,303 22,499 105,023

Cordia subcordata 55,503 20,464 6,821 82,789

Guettarda speciosa 6,690 84,250 119,218 42,486 35,438 1,059,512

Intsia bijuga 3,411 10,232

Morinda citrifolia 4,416 591,406 637,457

Neisosperma oppositifolia 3,411 53,763 3,411 12,329 83,146

Pandanus tectorius 16,502 3,342 13,643 10,096 57,226

Pemphis acidula 30,095 36,070

Pisonia grandis 3,411 6,821 30,696 374,292 505,245

Premna serratifolia 3,342 184,106

Scaevola taccada 56,648 254,918 1,604,115

Terminalia samoensis 7,913 22,473 30,386

Tournefortia argentea 16,374 5,056 54,677

 Total 97,898 290,024 1,013,291 20,464 470,888 114,713 4,536,740
24

RESOURCE BULLETIN PNW-RB-263

Figure 16—Damaged foliage is prevalent on coconut trees. Vines in crowns are also common in 

the Marshall Islands.

Figure 17—Insects and damage by other vegetation were the most common identifiable damaging 

agents in the Marshall Islands.

47%

22%

10%

6%

9%

3% 3%

Type of tree damage

Damaged foliage

Vines in the crown

Discolored foliage

Open wounds

Other

Broken/dead bole

Broken/dead roots

50.3%

18.6%

15.6%

11.7%

1.9%

1.3% 0.5%

0.1%

Primary damage agent

Insect

Vegetation

Unknown

Weather

Disease

Cutting

Fire

Physical

About 1.2 percent of the trees sampled during the inventory were dead. The 

most prevalent, identifiable dead trees were Cocos nucifera (49.6 percent of total 

dead), Guettarda speciosa (13.2 percent), and Neisosperma oppositifolia (8.9 

percent) (fig. 18).

Epiphytes

In the moist environment of the tropics, many plant species are found growing on 

longer lived trees. These epiphytes use the trees primarily for support, but they also 

use space, moisture, and nutrients that might otherwise be used by the tree. When 

the epiphytes accumulate over many years, their weight can be excessive, leading 
25

Republic of the Marshall Islands’ Forest Resources, 2008

Figure 18—Dead coconut (Cocos nucifera) trees were the most common of the dead species identified. 

Guettarda speciosa, Neisosperma oppositifolia, and Terminalia samoensis followed in prevalence as 

the most common dead trees.

0

5

10

15

20

25

30

35

40

45

50

Dead trees (percent)

Species

Cocos nucifera

Intsia bijuga

Guettarda speciosa

Neisosperma oppositifolia

Terminalia samoensis

Pananus tectorius

Bruguiera gymnorrhiza

Cordia subcordata

Tournefortia argentea

to the breakage of branches and occasionally snapping the stems of trees. In the RMI, 

we rated epiphytic loading on trees as a summation of loading on the bole, branches, 

and canopy. We estimate that about 92 percent of the trees ≥ 5 inches diameter at 

breast height in the RMI had few to no epiphytes, and less than 8 percent of the trees 

had moderate to high amounts of epiphytes (table 12).

Forest Dynamics

In the Marshall Islands, there is a wide range of forest characteristics and successional sere depending on latitude. In the drier northern atolls, we would expect slower 

successional replacement of species than in the wetter southern atolls, thus, recovery 

from disturbance may be quicker in the south. Over many of the atolls, the native 

vegetation has been replaced with coconut plantations (fig. 19). Other areas remain a 

mix of scrub and agroforest with species composition dependent on salt spray tolerance and rainfall amount (fig. 20).

Human populations have shifted and subsistence agroforestry is being replaced 

with a cash economy that relies on imported food, medicines, and building materials. 

Disturbance by military actions and the urbanization surrounding military installations have dramatically changed the vegetation of Kwajalein and Majuro. Food and 

water security have become important concerns for the atolls that are facing the loss 

of arable lands through urbanization and inundation from changes in sea level.
26

RESOURCE BULLETIN PNW-RB-263

Table 12—Estimated number of live trees ≥ 5 inches diameter at breast height on forest land 

by epiphyte loading (amounts of nontree vegetation in the canopy and branches) and species

Epiphyte loadings

Species None Low Moderate High All loadings

Number of trees

Allophylus timorensis 10,232 3,342 13,575

Artocarpus altilis 13,370 3,411 16,780

Artocarpus mariannensis 13,370 3,342 3,342 20,055

Bruguiera gymnorrhiza 23,875 23,875 23,875 71,625

Cocos nucifera 1,211,371 454,624 26,393 1,692,388

Cordia subcordata 91,816 11,110 9,095 112,021

Guettarda speciosa 225,386 109,582 55,505 20,332 410,805

Intsia bijuga 13,643 4,980 18,623

Morinda citrifolia 7,758 3,342 11,100

Neisosperma oppositifolia 162,057 7,867 16,712 186,637

Pandanus tectorius 434,861 88,995 57,742 19,640 601,238

Pemphis acidula 103,236 3,411 106,646

Pisonia grandis 143,045 16,780 30,696 3,411 193,932

Premna serratifolia 13,438 10,027 23,465

Scaevola taccada 8,256 8,256

Terminalia samoensis 29,756 8,880 38,636

Tournefortia argentea 111,790 41,915 3,702 5,056 162,463

 Total 2,603,890 795,486 237,090 51,780 3,688,246

Figure 19—Coconut plantations dominate the skyline of the Marshall Islands.

Steven T. Trimble
27

Republic of the Marshall Islands’ Forest Resources, 2008

Figure 20—The composition of native vegetation is determined by salt spray tolerance and drought tolerance.

Acknowledgments

The FIA Pacific Island inventories are the result of cooperative effort between 

a number of groups and agencies. The USDA Forest Service, State and Private 

Forestry in the Pacific Southwest Region has been a strong supporter of natural 

resource assessments in the Pacific Islands. Many thanks to the Pacific Islands 

Imagery Consortium partners for sharing costs on imagery and interpretation. 

Thanks to Nancy Vander Velde for species identification and training; Lisa 

Fischer and Zhafeng Liu (Leo) at the Remote Sensing Lab in the Pacific Southwest Region. We also thank Dale Weyermann, John Chase, and Chuck Veneklase with FIA for geographic information system, programming, and technical 

support. Dave Azuma, Tom Brandeis, David Clausnitzer, and Bob Gavenda 

offered very helpful comments on prior drafts.

Steven T. Trimble
28

RESOURCE BULLETIN PNW-RB-263

Metric Equivalents

When you know:	 Multiply by:	 To find:

Inches 2.54 Centimeters

Feet .305 Meters

Miles 1.609 Kilometers

Acres .405 Hectares

Square miles 2.59 Square kilometers

Cubic feet .028 Cubic meters

Tons 907 Kilograms

Tons per acre 2.24 Tonnes or megagrams per hectare

Cubic feet per acre .07 Cubic meters per hectare

Trees per acre 2.471 Trees per hectare

Degrees Fahrenheit (°F – 32)/1.8 Degrees Celsius

Literature Cited

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scientific names of trees and shrubs of Mariana, Caroline, and Marshall Islands. 

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Period of Record Monthly Climate Summary, 1953–2008. http://www.wrcc.

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Wood, G.B.; Wiant, H.B.; Roy, R.J.; Miles, J.A. 1990. Centroid Sampling: a 

variant of importance sampling for estimating the volume of sample trees of 

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