関東森林研究論 文71-1(2020)

Distribution and crown shape changing of Lindera praecox under theartificial Cryptomeria japonica and Chamacyparis obtusa canopies

Iwao UEHARA１
１ Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo 156-8502
Abstract: Lindera praecox is a woody plant of Camphoraceae, Lindera that has peculiar fragrance. It contains oily
component and it has been used for firewood. Its fruit had made desk lamp oil, too. Natural distribution of Lindera

praecox broads Honshu Island to Kyushu Island in Japan. It can grow on the floor and edge of artificial Criptmeria
japonica and Chamaecyparis obtusa stands. However, the characteristic features of Lindera praecox under thecanopies of Cryptomeria and Chamaecyparis stands has not been clear yet. Then, this study surveyed thecondition of distribution, density, and tree shape variation of Lindera praecox under the canopies condition. Thesurvey site was 50-year artificial Cryptomeria and Chamaecyparis stands located in 500 altitude in Kosuge village,
Yamanashi Prefecture. The stand incline was approximately 25 degree. Lindera praecox formed second canopies
under the canopies. Their crowns transformed their shape into two types that were vertical and horizontal
direction. Their branches and leaves might develop stepped shape for light reception and corresponding the incline.
These results suggested that the tree shape might be used as an indicator of the stand condition. It should keep

Lindera praecox without cutting under the Cryptomeria and Chamaecyparis canopies at steep stands to prevent
soil erosion.
Key word: under the canopies of Cryptomeria japonica and Chamaecyparis obtusa, Lindera praecox, distribution,
characteristic features

スギ・ヒノキ人工林冠下におけるアブラチャンの分布と樹形変化
上原 巌１
１ 東京農業大学 地域環境科学部
要旨：アブラチャン（Lindera praecox)は、クスノキ科クロモジ属の樹木であり、特有の芳香を持ち、薪炭のほか、その実から採れる油は読書灯などに用いられてきた。アブラチャンは、本州～九州にかけての温帯に自生し、スギ、ヒノキなどの造林地の林縁、林床でもよく見られる。とりわけ林床の植生が貧弱になりやすいスギ・ヒノキ人工林の場合、アブラチャンの発生、分布は、土壌流亡抑制などの意味においても重要な意義を持っている。しかしながら、その林冠下の発生密度や分布の状況、また樹形の変化などについてはあまりよく知られていない。
そこで本研究では、奥多摩源流の山梨県小菅村のスギ・ヒノキ人工林（標高約 500ｍ）において、その林床のアブラチャンの分布状況と樹形の特徴を調べてみた。調査の結果、アブラチャンはスギ・ヒノキ林冠下に二層目となる低林冠を形成し、地形の傾斜に適応して樹冠を階段状に連ねて発達させ、また受光のために柔軟に樹形を変化させていることなどが明らかになった。これらのことから、スギ・ヒノキ林冠下のアブラチャンは除伐をせずに残存させ、土壌流亡抑止などに供すること、またその樹冠、樹形の形態から、林冠下の照度状況の指標ともなることなどが考えられた。
キーワード：ヒノキ林冠下、アブラチャン、分布、樹形特性

Ⅰ Introduction

component. It has been used for firewood and its fruit

Lindera praecox is a woody plant of Camphoraceae,

had been used to make desk lamp oil, too (1). Its

Lindera. It has peculiar fragrance and contains oily

natural distribution broads Honshu Island to Kyushu－53 －（受理日 2020 年 2 月 3 日）

Island in Japan. It can grow on the floor and edge ofwas measured twice per a leaf and totally 20 leaves

artificial Criptmeria japonica and Chamaecyparis

were measured on each Lindera praecox seedling in

obtusa stands. However, the characteristic features ofeach plot.

Lindera praecox under the canopies of Cryptomeria

4. Surveying natural regeneration This researchand Chamaecyparis stands has not been clear yet.

counted all regenerated seedlings of woody plant at

Recently, broad-leaf trees regeneration at artificial

each plot and measured all tree height of the each trees

needle-leaf forests floor has become more important,(above 0.1m).

because it is useful to increase diversity of vegetationand it sometimes makes mixed forests without

Ⅲ. Results and Discussion

planting, too (2) (6). Floor vegetation is also important1.

Appearing species numbers of each plot

for preventing soil erosion at steep location. Then, thisTable 2 shows the appearing species numbers andstudy surveyed the condition of distribution, density,appearance percentage of Lindera praecox of eachand tree shape variation of Lindera praecox under theplots. The average appearance percsentage of Lindera

canopies condition.

praecox was about 20%.Table 3 shows the conditions ofLindera praecox at each plot.

Ⅱ Materials and Methods
1. Site The survey plots were set in an artificial 50-Table 2. Appearing species numbers of each plots

year Criptmeria japonica and Chamaecyparis obtusa

PlotABCD

stand. They were located in the 500m high from sea

Species numbers

1612710level in the Kosuge village, Yamanashi Prefecture.

Percentage of Lindera praecox

Each survey plot area was 100 ㎡ and totally 4 plots(%)

21192620

were surveyed in this study. Table1 shows average treeheight, average DBH, stand density, crown area, andTable 3. Conditions of Lindera praecox at each plot

relative illumination in each plot.
Average tree height

Table 1. Conditions of each survey plot(m)ABCD

Average tree height (m)

19

18.2

16.2

21

Average DBH (cm)

29

27.4

25.7

25

Stand density (number/a)

58

119

Volume (㎥/a)

3.6

4

5.4

5.2

Total canopy area

Canopy area (㎡/a）

4688

5854

(㎡/100 ㎡）

Average Relative illumination (%)

105.4

7.4

7.4

Average DBH (mm)Stand density(seedlings/100 ㎡)ABCD

0.46

0.95

0.75

0.55

（±0.3）（±0.4）（±0.4）（±0.3）

14.5

12.4

18.2

15.4

(±9.1）（±8.8）（±9.6）（±12.8）

23

24

20

19

16

27

6.5

1.5

Next, Fig. 1 to 4 show the tree canopies ofThe stand slope was approximately 25 degree. All

Cryptomeria and Chamaecyparis obtusa (left) andsurvey plots were on the north-facing stand. Forest soil

Lindera (right) of Plot A to D. Square shows 100 ㎡ andwas brown forest soil (7.5YR 6/5, 10YR 6/6: Manthel× shows the vertical shaped stand of Lindera.

Colors) and soil pH was 4.5 to 4.9.
2. Appearance rate This research surveyed theappearance rate and space dominant condition ofLindera praecox under the canopies of Cryptomeria
japonica and Chamaecyparis obtusa.
3. Chlorophyll amount (SPAD) This research
surveyed chlorophyll amount of the Lindera praecox bymeasuring SPAD analyzer (Minolta SPAD-502). SPAD－Fig. 1 Tree canopies of Plot A(Left: Cryptomeria & Chamaecyparis, Right Lindera)

54 －関東森林研究71-1(2020)

Lindera umbellata
Clerodendrum…
Callicarpa mollis
Lindera praecox
Ilex macropoda
Callicarpa japonica(m) 0Fig. 2 Tree canopies of Plot B

0.5

11.5

22.5

Fig.6 Space dominant conditions of plot B(Left: Cryptomeria & Chamaecyparis, Right Lindera)
Lindera umberallata
Lindera praecox
Callicarpa japonica
Fraxinus sieboldiana
Acer sieboldianum(m) 0Fig. 3 Tree canopies of Plot C

1234

Fig.7 Space dominant conditions of plot C(Left: Cryptomeria & Chamaecyparis, Right Lindera)
Lindera praecox
Meliosma tenuis
Lindera umbellata
Callicarpa japonica
Corylus sieboldiana(m)Fig. 4 Tree canopies of Plot D

00.5

11.5

2Fig.8 Space dominant conditions of plot D(Left: Cryptomeria & Chamaecyparis, Right Lindera)
3.Relative illumination of the places of Lindera
There was no correlation between high story canopies

praecox appearance

condition and appearance of Lindera praecox.

Therewasnocorrelation

betweenrelativeillumination and appearance of Lindera praecox.
2.Space dominant conditions of each plot
Fig. 5 to 8 show space dominant conditions of each

4. Chrolophyll amount (SPAD) of each plots

plots. Each figures show species over 0.1m height.

Table 4 shows chrolophyll amount (SPAD) of Lindera

praecox on each plots. There was no correlation
between SPAD and relative illumination, density, andMorus austrails
Lindera umbellata
Callicarpa dichotoma
Fraxinus sieboldiana
Lindera praecox
Meliosma tenuis
Callicarpa mollis(m)tree height of Lindera praecox. SPAD datas also
showed no significant difference at the stories. These
results suggested that Lindera praecox thoroughly
contributes chlorophyll regardless of light condition.
00.5

11.522.5

Table 4 Chrolophyll amount (SPAD) of each plots

Fig.5 Space dominant conditions of plot A.

－55 －Plot A

40.0 (±3.6）

Plot B

39.5 （±3.4）

Plot C37.9 （±3.2）

Plot D

40.8 （±1.4）

5. Soil Moisture Content

Fig.11 showed the root system of Lindera praecox.

Table 5 shows soil moisuture content. These results

Roots are mainly supportive roots and hair roots were

showed that distribution of Lindera praecox isfew.

controled by the soil moisture, too (R=0.7378).
Table 5. Soil moisture content (%)
ABCD

Soil Moisture

38.5

31.8

32.4

36.5Content (%)(±5.1）(±7.5）(±2.3）（±6.9）

23242019

Number ofLindera praecox

Fig.11 Root system of Lindera praecox
Ⅳ．Conclusion

6.Other features

Lindera praecox formed second canopies under theThis research showed the appearance percsentage ofcanopies. Fig. 9 showed the stepped shapes and

Lindera praecox was about 20% under the artificial

horizontal shapes of Lindera praecox. It seems that

Cryptomeria japonica and Chamacyparis obtusa stand.

Lindera praecox can change the tree shape to adopt theIt might thoroughly contribute chlorophyll regardlesslight condition under the canopies. There are two typesof light condition. It can grow under the tree shade ofof tree shape which are vertical and horizontal (Fig.10).

Cryptomeria and Chamacyparis obtusa by changing

There were sprout regenerations in each plots, too.

their tree shapes. Therefore, the tree shape can be an

Cryptomeria japonica and Chamaecyparis obtusa

indicator of the stand condition, too.

stands sometimes easily lose floor vegetation. Natural

Next step is considering how to promote the growth

regeneration is sometimes more effective to keep

and cultivation of Lindera praecox on the artificial

vegetation at the difficult stands and it is easier toforest floor.

adapt the stand condition (2) (3) (4) (5). Therefore,

Lindera praecox is one of the important plants for

References

preventing soil erosion and keeping floor vegetation.

(1) Hayashi, Y. (1969) Diagram of useful trees (有用樹

On the silvicultural point of view, it should keep

木 図 説 ). pp. 255. Seikodoshinkosha. Tokyo. (inLindera praecox without cutting at steep location ofJapanese)(2) Kawahara, T. (1994) Art of tending regenerated

Cryptomeria and Chamaecyparis stands.

broad-leaf trees at artificial needle-leaf tree stand.
Broad-leaf forest practice （広葉樹林施業）． pp.
154-173. Zenrinkyo, Tokyo.(in Japanese)(3) Nyland, R.D. (2002) Silviculture-Concepts andApplications. pp.27-31. Waveland Press, Long
Grove, IL.
Fig.9 Tree shapes of Lindera praecox under the(4) Smith, D.M. (1986) The practice of silviculture. pp.
45-46, 128-129. Wiley, New York.

canopies of Chamaecyparis obtusa.

(5) Uehara, I. (2018) Silviculture Field Note (造林学フィールドノート). pp.123-133. Corona-sha. Tokyo.
(in Japanese)(6) Uehara,I.

(2020)

Distribution

ofnaturalregenerated Lindera umbellata at artificial

Chamaecyparis obtusa floor by several thinning

Fig. 10 Two types of tree shape.

rates. Kanto Forest Research. 70(2)(left: vertical shape, right: horizontal shape)－56 －