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Our Forests

The University of Tokyo Hokkaido Forest

1. History and Summary

The University Forest is located in the central part of Hokkaido Island with sub-boreal mixed forest of evergreen conifers and deciduous hardwoods. It was established in 1899 after 30,000 ha of virgin forests were transferred from the Hokkaido Government. Since then part of this area was cultivated by farmers and therefore current forest area is 22,715 ha. Currently about 20,000 ha are used for experimental forestry management and the remainder are reserve forests and arboretum. In 1958 ‘Rinbun-segyo-ho’, a method of stand-based natural forest management, was initiated. The objective is to allow both logging and the public function of forests to coincide by maintaining a sustainable forest ecosystem. Since 2006, the 12th management plan has been in operation. Under Rinbunsegyo-ho principles, the selection management cutting cycle in the forest is prolonged to 15 years and the yield percentage in each selection stand is decided by the previous cutting regime.

2. Location and Facilities

The University Forest is located in the Central Hokkaido (142º 18´-40´ E, 43º 10´-20´ N), in the Furano City Administrative District including Yamabe, Higashiyama and Rokugo. The head office and laboratories, arboretum and nursery are located near Yamabe. There are seminar houses and a forest museum in Rokugo.

3. Geography and Climate

There are two main river basins (the Nunobe basin and the Nishi-tappu basin) in the University Forest, both of which join the broad Sorachi river. The elevation ranges from the lowest point of Nunobe (190 m a.s.l.) to the highest point of Mt. Dairoku (1,460 m a.s.l.). During the Quaternary Period, eruptions of the Daisetsu mountain system covered the area from the north-east (Mt. Dairoku) to its center. The geology is characterized by limestone and metamorphic rocks like hornfels that belong to the Hidaka mountains at the southern boundary, and sedimentary rocks like chert, sandstone, mudstone and pillow lava that belong to the Yubari mountains at the western boundary. Major stratified soils include mountain black soil, podzolic, dark and brown forest soil. Dark forest soil is seen in the coniferous forest zone at elevations between 500 - 800 m a.s.l., and brown forest soil mostly occupies conifer - broadleaved mixed forests below 600 m a.s.l.. Low and moist black soil, gleyed forest soil and forest litter-debris soil are present in isolated localities. The mean temperature at the Arboretum (230 m a.s.l.) during 1996-2005 was 6.3 ºC. The maximum and minimum temperatures were 35.4 ºC and -26.8 ºC, respectively, ranging over 62 ºC. The mean annual precipitation was 1,254 mm, and the maximum snow depth was 88 cm. The period of snow cover was usually starts at the end of November until the beginning of April.

4. Forest Conditions

The University Forest is a Pan-mixed forest with coniferous and broad-leaved species between the cool-temperate and the sub-boreal zone. Abies sachalinensis is one of the dominant tree species in the Pan-mixed forest type, occupying a wide range of altitudes from low elevations (200 - 300 m a.s.l.) to the upper forest limit (about 1,200 m a.s.l.). Other predominant tree species include Picea jezoensis, Quercus crispula, Kalopanax pictus, Fraxinus mandshurica, Betula maximowicziana and Tilia japonica.

5. Research and Education

(1) Research

a) The Stand-Based Forest Management System

This University Forest has conducted experiments on the sustainable management of natural forests around a stand-based forest management system that enables biological diversity to be maintained and forest ecosystems conserved. The research topics in the experimentally managed forests include: 1) analyses of forest ecosystems, 2) characteristics of existing tree species, 3) analyses of stand structure and stand growth, 4) technological development of natural regeneration enhancement and 5) optimization and systematization of forest management practices.

b) Artificial Plantations

The area of artificial plantation is approximately 3,300 ha with mainly Abies sachalinensis, Picea glehnii and Picea jezoensis. Density management of planting and thinning is one of the major concerns for artificial plantations. Commercial trees of Picea jezoensis plantations are scarce in Hokkaido and, therefore, these plantations are important models for resource recovery of the species in Hokkaido. Recently, low-density planting with around 1,000 trees/ha of conifers and establishing mixed forests by naturally-regenerated hardwoods has become more common practice.

c) Conservation and Management of Forest Genetic Resources

Collection and conservation of sub-boreal forest genetic resources, molecular ecology, tree improvements of inter-specific hybridization of larch species has been carried out in the University Forest. Genetic diversity and structure of major tree species, such as Abies sachalinensis, Betula maximowicziana and Fraxinus mandshurica var. japonica has been investigated using molecular markers in natural forests. Nearly 300 tree species from northern America, northern Europe and northern Asia have been collected in the arboretum garden and in the test plantations.

d) Forest Road Network

A high density network of forest roads is essential infrastructure in natural forest management. Forest roads have been constructed under the Stand-Based Forest Management System, and their overall length reaches 933 km with a road density of 41 m/ha. Technological improvement concerning the efficiency of forest road maintenance is an important research topic. From the viewpoint of stand structure, forest roads are regarded as continuous gaps and have the function of temporary soil and water retention.

e) Directly Managed Logging Operations

The directly managed logging operations play a significant role in the experimental management practices. The objectives are to establish appropriate logging methods in selection systems, to harvest forest resources while adapting to timber markets, to introduce and test highly efficient forest machinery, and to develop operating techniques.

f) Development of a Database using GIS

This University Forest has recorded and accumulated long-term and largescale forest information through 50 years of experimental practices. To manage and utilize the data in an integrated manner, we are working on the development of a spatial database of forest information using GIS (Geographical Information System).

g) Forest Protection

Silvicultural management for reducing damage to spruce tree species by Ips typographus japonicus has been developed in the University Forests. The life history of Parna kamijoi, which increases in density over an interval of three years, has recently been a subject of investigation. The method for reducing damage from snow blight disease that seriously damages seedling production of Picea jezoensis has been examined in the nursery. Recently, population dynamics of Cervus nippon yesoensis in the University Forest and neighboring agriculture land has been monitored to reduce browsing and damage to crops and trees.

h) Recovery Processes of Windthrown Site

A windfall site of about 8,735 ha was created as a result of the typhoon of 1981. The recovery process of the forest structure after wind damage was examined, and research topics included the change of damaged stand structure, the successional process and trend of floristic composition, insect and disease damage to the trees in relation to environmental changes. Reforestation experiments in severely damaged sites have been conducted.

i) Integrative Investigations of Valley Head Areas

Since 1983, runoff characteristics of the sub-boreal zone and long term restoration process of vegetation of forest damaged by typhoon has been surveyed. Starting 2004, field specialists have been organized to investigate water quality, temperature, flow rate, aquatic organism, riverside vegetation, soil, and geology.

j) Investigation of Ecosystems in Limestone Areas

It is known that particular rocks such as serpentine and limestone have influenced vegetation. Regeneration and growth in natural forests and re-vegetation after mining activities has been investigated.

k) Research on Forest Dynamics in Long Term Ecological Research Sites

Long term research on the dynamics of natural forests has been conducted every five or ten years at the large scale plots established in the Mae-yama area (36 ha) and the Iwana-zawa area (19 ha). The data obtained in these research sites is very important and valuable for evaluating the long term effect of environmental changes on the composition and structure of natural forests. The differences between over-mature natural stands and selection cutting stand have also been compared.

l) Development of a Sustainable Hardwood Production System

As a sustainable resource management of valuable Quescus crispula hardwoods, approx. 26,000 large-sized and matured trees are registered individually. The tree density and size structure of Q. crispula dominating stands are controlled by thinning. The regeneration is promoted by scarification, seeding and planting.

(2) Education

The University Forest is used as a research field by under-graduate and graduate students of the University of Tokyo and other universities and by researchers in various institutes. Excursions and field education sessions for learning silvicultural management systems of the University Forest have recently been increasing. Since 1994 the University Forest has held extension lectures for the general public and, since 1999, it has been used for childrenユs activities. In 2007, the Jinjayama area was opened for viewing nature, and signboards and a rest house were set up for recreation and recuperation of many people.