The Arboricultural Research Institute

1. History and Summary

  The Arboricultural Research Institute (ARI)A of the Tokyo University ForestsA was established in 1943 for the study of multiple-use woody perennials grown in tropical and sub-tropical conditions. About 240 ha of private forest at AonoA MinamiizuA Shizuoka prefecture were purchased for ARI by Tokyo University Forests at that time. In 1948A the offices were moved to the KanouA Minamiizu and an operation station was opened at Aono. In 1955A ARI obtained the adjacent forest to the Kanou officeA and also a hot spring. ARI maintains 246.1 ha of forest area at present. NowadaysA arboricultural and silvicultural studies on tropicalA sub-tropical and warm-temperate zone forests are conducted by using the forest and the green houses heated by the hot spring.

2. Location

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

3. Land conditions

  The forest area geologically consists of the Shirahama stratum of the Miocene. Brown forest soils dominate the forest area of ARI. The forest at Aono is steep and complex and has an altitude from about 100 to 500 m. The annual mean temperature over the last 30 years has been 15.0 and annual precipitation is 2A270 mm at the Aono weather station.

4. Forest conditions

  The forest of ARI is located in the warm-temperate evergreen broad-leaved forest zone. Secondary forest of Western Chinquapin (Castanopsis cuspidata) mixed with evergreen oaksA Neolitsea sericeaA Camellia japonica and other evergreen species dominates. OccasionallyA deciduous forest occurs consisting of Quercus serrataA Prunus spp.A Rhus succedaneaA Alnus sieboldianaA Cornus controversa and other species. In the lower-story of the forest there are abundant Hydrangea involucrataA Aucuba japonica and Eurya japonica. Ferns (Arachniodes standishiiA Pteris wallichiana etc.)A Ardisia pusillaA Ardisia japonicaA and Damnacanthus major are typical species on the ground.

  Manmade forests of exotic and domestic species cover almost 60 % of the forest area. A forest of 80-year or older Cinnamomum camphora covers an area of 40 ha. It is the most attractive forest among the manmade forests of ARI. Other manmade forests are 35-years-old or less.

5. Research and Education

Fundamental silvicultural research is conducted on domestic and exotic multiple-use tree species. Cinnamomum camphoraA Aleurites cordataA Rhus succedaneaA Acacia spp.A Eucalyptus spp. etc. have been studied for their waxesA perfumesA pharmaceutical useA tannin etc. Studies concerning the afforestation of tropical forest land are also important tasks of ARI.

(1) Silvicultural studies on Eucalyptus and Acacia

  Species of Eucalyptus grow very fast and contain lots of useful chemical components. Many useful species for environmental conservation and multi-purpose use are recognized. Species of Acacia having root nodules are tolerant of infertile land. They are thought to have potential for the reforestation of denuded tropical forest.

  To select the best species for multiple use in Japanese forestryA 67 species of Eucalyptus and 35 species of Acacia species are under test.

(2) Studies for reforestation of tropical forest

To support the studies of reforestation of tropical forestsA silvicultural and physiological studies of tropical species of Acacia and DipterocarpaceaeA for exampleA are being undertaken. In particularA the vegetative propagation of these species by tissue culture and other methods are the main targets of research. Studies of the tolerance of Acacia to acidic soil are also important. In additionA to develop technologies of reforestation using tree-microbe symbiotic systemA studies of the interactions between Acacia and root-nodule bacteria are conducted.

(3) Other studies

  About 200 tropical and sub-tropical multi-purpose tree species have been introduced to the green house. They are used as material for the study of sexual and asexual propagation and physiology.

  Silvicultural studies on multi-purpose tree species such as Cinnamomum camphoraA Aleurites cordataA Cunninghamia lanceolata and Metasequoia glyptostroboides are one of the main activities of the experimental forest at Aono. Silvicultural studies of domestic tree species such as Japanese Cedar (Cryptomeria japonica)A Hinoki Cypress (Chamaecyparis obtusa) and Pinus thunbergii are also important for the establishment of adequate treatment methods for regional forestry.

(4) Education and Training

  Silvicultural training and education concerning tropical forestryA multiple-use tree species and forests of the warm-temperate zone are also important at ARI.

6. Green house

  A Green house heated by hot spring (100 A 200 L / min.) was constructed in 1947. It is 260 m2 in area and 7 m high. In it are kept about 350species of tropical and sub-tropical treesA collected as a genetic resource during the last 5 decades. They are used for education on tropical trees and as material for research.