‫ە‬A Case of Utilizing ResultsEnacting the Handbook for
Measures to Prevent
Typhoon Damage to Planted
Trees in Cities



MATSUE Masahiko, HeadIIZUKA Yasuo, Senior Researcher
Landscape and Ecology Division, Environment Department
NAGAHAMA Yosuke, Chief Official
Planning Division, Planning and Research Administration Department咁 咂Damaged treesarrives
1. Introduction
Before a typhoon arrives, a tree management system isPlanted trees in cities, beside roads and in parks forquickly established, the soundness of the trees
example, are damaged, even falling over, under theconfirmed, and preventive measures taken at trees
impact of powerful wind during typhoons. In addition
which are vulnerable to damage (pruning, installing ato damaging surrounding structures or blocking traffic,
wind blocking net, etc.). When a typhoon arrives,
they can even injure people.
emergency measures are taken to deal with damaged
So in order to mitigate typhoon damage to trees
trees (cutting down and removing, etc.), and after theplanted in cities, we have taken Okinawa, which istyphoon has passed, full-scale measures to deal withstruck by more typhoons than other parts of Japan, as
damaged trees (standing the trees or replacing thean example to perform a fact-finding survey of
support columns, etc.) are taken and the causes of thetyphoon damage to clarify the causes of this damage,damage are clarified. and based on the results, establish tree planting(4) Daily maintenance
methods to nurture trees highly resistance to typhoon In order to nurture highly typhoon resistant trees
damage.planted in cities, it is important to regularly check the2. Outline of the Handbook for Measures toPrevent Typhoon Damage soundness of trees, and to do so, necessary to ձ This handbook consists of the following four
perform daily inspections and 㸦 , 㸧 ղ  soundnesschapterssurveys and ճappropriately manage all trees.
(1) Factors causing typhoon damage
3. Announcement of the results
Typhoon damage is broadly categorized as fallen
The results are explained based on trees and the treetrees, bent trees, broken trunks, and broken branches,
planting environment of Okinawa, but the basic
and the causes of these types of damage are ձtyphoon damage prevention measures can be applied
typhoon exceeding a specific scale (Fig. 1), ղin all regions of Japan, so the results have been
selection of species unsuited for
Common garcinia (Garcinia subelliptica)
350
conditions at the location, ճ(Root system: distributed and deep)
insufficient planting base, մ  low
Branch spread: 3.5m
300
quality planting, and յ  low quality
250
maintenance ⿕(2) Basic typhoon damage prevention
ᐖ 200ᮏ
measuresᩘ150ᮏ
In order to mitigate typhoon damage
Tree height: 6.0mto trees planted in cities, it is important100
to correctly plan, design, and execute the50tree planting. Specifically, it is necessary
to give full consideration to ձ0㻜㻚㻜㻌㻡㻚㻜㻌 㻝㻜㻚㻜㻌 㻝㻡㻚㻜㻌 㻞㻜㻚㻜㻌 㻞㻡㻚㻜㻌 㻟㻜㻚㻜㻌 㻟㻡㻚㻜㻌Consolidated soil
Effective soil layer
selecting species, ղ  layout, ճMaximum wind speed᭱኱㢼㏿䠄m/s䠅
Drainage layer
providing the planting base (Fig. 2), andFigure 1. Maximum Wind Speed and Figure 2. Example of Provision ofմ installing support columns.
Number of Damaged Trees
the Tree Planting Base(3) Measures taken when a typhoon

A Case of Utilizing Results(Key words) Planted trees in cities, typhoon damage, tree planting method, maintenance, Okinawa published as Technical Note of NILIM No. 621.
We look forward to this handbook being used as abasic document to be applied to improve tree planting
technologies in Okinawa and throughout Japan,
contributing to the conservation of rich green living
environments.
http://www.nilim.go.jp/lab/ddg/index.htm‫ە‬A Case of Utilizing Results