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Our Forests

Arboricultural Researchi Institute

1. History and Summary

The Japanese name for the Arboricultural Research Institute (ARI) is “Jugei-kenkyusyo”. “Jugei” can be translated as meaning arboriculture. The word “Jugei” contains the ideas of familiarizing oneself with trees, making the best of trees, and nurturing them. The market for many forest products has been declining by reason of a lack of economic competitiveness and petrochemical products have replaced them in many end-uses. But the Institute questions whether this is truly economic and wants to bring this question to the front of people’s minds. The Institute’s position is that forest biomass should be returned to the centre of daily life. Part of the mission of the Institute is to pass this “Jugei-mindset” to the next generation through education and research.

The ARI was established by the Tokyo University Forests in 1943, during World War II, at Aono, Minamiizu, Shizuoka prefecture. Its purpose was the study of tropical and sub-tropical trees for non-wood forest products. In 1944, about 0.6ha of land at Kanou, Minamiizu, was leased and a large wooden greenhouse was built on the site in 1947. In 1948, the office was moved from Aono to the Kanou site. In the same year, a hot spring was struck (100oC, 200L/min.), which has been utilized to heat the greenhouse which was renovated in 2009. At present, by utilizing the greenhouse (area 260m2, height 7m) and the experimental forest at Aono (total area 246.1ha), various trees are cultivated for non-wood forest products and the provision of educational programs which use such trees as teaching materials.

2. Location

The laboratory and office are located at Kanou, Minamiizu, Shizuoka prefecture at the southern end of the Izu peninsula. From the Kanou office, famous sight-seeing destinations such as Yumigahama (6km) and Cape Irozaki (13km) are readily accessible. ARI is about 12km away from Shimoda station on the Izu Kyuko line and it takes about 25min by bus from Shimoda station to Kanou itself. The Aono field station is a further 8km away from the Kanou office - about 15min by car.

3. Land condition

Geologically, the forest area consists of the Shirahama stratum of the Miocene. Brown forest soils dominate the forest area of ARI. The topography of the forest area at Aono is steep and complex and has an altitude which ranges from about 100 to 500m. At the Aono weather station, annual mean temperature over the last 10 years was 15.4 oC and annual precipitation was 2,299mm. The average number of days when the temperature dropped below zero in each year was 24.6. It rarely snows.

4. Forest condition

The forest of ARI is located in the warm-temperate evergreen broad-leaved forest zone, and thus Castanopsis species and oak trees potentially dominate. Most of the forest area is occupied by a secondary forest of Western Chinquapin (Castanopsis cuspidata), mixed with evergreen broad-leaved trees such as Quercus acuta, Q.salicina, Neolitsea sericea, N. aciculata, Camellia japonica and Cinnamomum japonicum, which were once used as coppice but have now been abandoned. Occasionally, deciduous broad-leaved trees such as Q.serrata, Prunus species such as Prunus speciosa and P. jamasakura, Rhus succedanea, Alnus sieboldiana, Swida controversa, Mallotus japonicas and Zanthoxylum ailanthoides can be found. In the lower-story of the forest there are abundant Aucuba japonica and Eurya japonica. Ferns such as Arachniodes standishii, Gleichenia japonica and Pteris wallichiana, and shrubs or undershrubs such as Maesa japonica, Rubus buergeri, Ardisia japonica and Damnacanthus indicus are typical species on the forest floor.

Of the Aono experimental forest area, 23.5% is occupied by plantations of conifers such as Cryptomeria japonica and Chamaecyparis obtusa, and 26.5% by plantations of useful broad-leaved trees such as Cinnamomum camphora, Eucalyptus species, Acacia species and the tung tree (Vernicia fordii). A plantation of 100-year or older C. camphora covers an area of 48ha, whereas other manmade forests are 55-years-old or younger.

5. Education

1) Fieldwork Seminar and Practical Training

In recent years, ARI has been focusing on fieldwork seminars designed for students of the junior division of the College of Arts and Sciences. The aim is to have students think deeply about common problems involving abandoned bamboo forests and former coppice forests through active learning programs. Practical training is also provided for students of the International Technical Cooperation for Rural Development. In addition, “Practice and Experiments in Landscape Planting” for students of Bio-Environmental Science Courses is carried out in ARI at the Experimental Station for Landscape Plants.

2) Educational programs using greenhouse plants

About 350 tropical and subtropical plants are cultivated and exhibited in the greenhouse. Currently the process of developing educational programs utilizing familiar tropical plants such as coffee, cacao, vanilla, and cassava is being undertaken.

6. Research

1) Studies of useful broad-leaved trees

In the Aono experimental forest, silvicultural studies of some tree species not found in this geographical area have been conducted. For example, possible elite Eucalyptus species have been selected through field adaptation tests over several decades and ARI is now planning to screen the selected species again for their growth. In addition, attempts are being made to utilize camphor trees and tung trees in educational programs.

2) Studies on environmentally-conscious management of warm-temperate forests

About half of the Aono experimental forest area is occupied by secondary forests of Castanopsis and Quercus species which exhibit typical lower warm-temperate vegetation.

Long-term ecological research has been conducted to understand the dynamics of secondary forest communities dominated by evergreen trees.

7. Contribution to society

1) Open seminars

Seminars for ordinary citizens and students are held several times a year. These include guided tours of the woods, bird-watching, and forest lectures for children. In addition, ARI participates in the educational activities and nature education of elementary schools.

2) Greenhouse

The greenhouse is open to the public from 9:30 to 16:30 throughout the year. In addition, open seminars on tropical plants are held at regular intervals.