The University of Tokyo Chiba Forest (UTCBF)

1. History and Summary

The University of Tokyo Chiba Forest (UTCBF) was established in 1894 and is the oldest university forest in Japan. It started with woodlands of only about 330 ha around Kiyosumi. Soon after, in 1897, Okuyama woodlands in the northern district of Kiyosumi were added and the total area of forest approached its current level of around 2,169 ha. At its inception, the area was mostly occupied by coppice forests consisting of evergreen broad-leaved trees such as Quercus spp., Castanopsis cuspidata var. sieboldii, Machilus thunbergii, Cliyera japonica, and high forests made up of Abies firma and Tsuga sieboldii.

Since the establishment of UTCBF, artificial reforestation with Cryptomeria japonica and Chamaecyparis obtusa has been carried out. At present their combined area has reached 825ha. These planted forests hold a wide range of age class distributions, from young stands to very old growth ones (planted in 1835). They are, therefore, representative of experimental and educational domestic planted forests. UTCBF also contains various kinds of experimental plots, protection forests, and demonstration forests of indigenous and exotic species. These are used for field studies in various aspects of forest science.

This University Forest is divided into three tracts of almost equal size; Kiyosumi in the southern district, Fudago in the northeastern district and Godai in the northwestern district. Its southern part is included in the Minami-Boso Quasi-National Park and the northern part is in the Yorokeikoku-Oku Kiyosumi Chiba Prefecture Park. The Kanto Hiking Trail, prepared for excursions encircling the Metropolitan area, passes through UTCBF. All parts of the University Forest are bird and animal sanctuaries. To preserve nature from human interference, limitations on the collection of plants and animals have been established and driving on forest roads is restricted. The flora is abundant in species. The list of vegetation shows more than 280 tree species and about 800 species of herbs, including around 120 fern species. The fauna is equally abundant and varied as the flora.

2. Location

UTCBF is located in the southeastern part of the Boso Peninsula. It extends from 140º 5'33" to 10'10"E and from 35º 8'25" to 12'51"N. The northern part is situated in Kimitsu city and the southern part is in Kamogawa city in Chiba Prefecture.

3. Land condition

The Kiyosumi mountain district is the water divide of the University Forest. The southern part of Kiyosumi is the basin of the Futama River which drains directly into the Pacific Ocean. The northern part is the upper basin of the Obitsu River which drains into Tokyo Bay. The forest is characterized for the most part by altitudes of 50 - 370m. The contour pattern is complicated and varied, and the slopes are generally very steep. The geological structure consists of marine deposits from the Neogene period, partly covered by non-marine deposits from the Quaternary. There are abundant faults. The underlying rock, consisting of sandstone, conglomerate, mud stone and tuff, has a tendency to weather easily.

The monthly mean temperature in midwinter is about 4ºC and in midsummer about 25ºC. The annual mean temperature is approximately 14ºC and the annual precipitation is around 2,200 mm.

4. Forest condition

The stands in the University Forest are divided into five categories according to their vegetation type and research and education objectives.

(1) Coniferous natural forest (387ha)

Coniferous natural forests consist of Abies firma and Tsuga sieboldii in the upper-story, evergreen Quercus spp. and Castanopsis cuspidata var. sieboldii in the under-story layer. The coniferous natural forests, which characterize the vegetation of the southern part of the Boso Peninsula, can only be found in this University Forest and the adjoining Motokiyosumi mountain district.

(2) Broad-leaved natural forest (949ha)

Broad-leaved natural forests were worked as coppice. With the decline in charcoal making, these forests were left to grow. The forests are divided into Castanopsis-evergreen Quercus forests, Q. serrata forests, Zelkova-Acer forests, and others.

(3) Planted forest (825ha)

Most of the planted forest stands consist of Cryptomeria japonica and Chamaecyparis obtusa. Old growth Cryptomeria japonica stands are found in in Minamizawa (planted in 1896), Gobozawa (1906) and Gotagura (1894). Old growth Chamaecyparis obtusa stands are found in Obera (1900) and Metaki (1903).

(4) Demonstration forest (56ha)

Indigenous demonstration forests can be found in Nagasaka, Sanbonmatu, Hayao and elsewhere, and exotic demonstration forests in Nanamagari, Maezawa and elsewhere. In addition, old growth Cryptomeria japonica stands that were planted before the establishment of UTCBF can still be found in Imasumi, Sakuragao and Jindajo.

(5) Nurseries, seed orchards and other areas (8ha)

Fertilization, regeneration, and selection for mother trees are carried out in seed orchards and breeding arboretums in order to obtain high quality seeds and cuttings. In nurseries, seedling production and changes of transplant beds are carried out under a yearly production plan.

5. Education

UTCBF has many experimental forests, educational forests and a forestry museum. These are used as teaching resources for students and open lectures to the public. The important student practical courses are as follows. Graduate School of Agricultural and Life Sciences; field sciences, Faculty of Agriculture; training for forest science basicsI, forest mensuration, forest management, Faculty of Science; geology and Faculty of General Education; seminars and general subjects.

6. Experiments and research

The 13th Education and Research Plan of the University of Tokyo Chiba Forest (2011-2020) involves four main research topics;"sustainable management of planted forests", "breeding and propagation of commercial trees", "conservation and reproduction of endangered plant species" and "wildlife control for the protection of warm-temperate forest".

Considering the first topic, "sustainable management of planted forests", the University Forest holds a large area of old growth planted forest. Stands with trees aged 80 years or more occupy 37% of the total area of the 825 ha of planted forests, and those with trees 100 years and older occupy 12%. With the practical use of these old growth planted forests, the following research and experiments are being undertaken; development of a long rotation system under superimposed rotations and the conversion of pure stands with poor accessibility to mixed stands.

The breeding and propagation of commercial trees involves a seed orchard of pine wilt disease-resistant pines, which was developed in 1983. The UTCBF has selected resistant individuals and has propagated them effectively. The relationship between environment and resistance in Japanese black pine (Pinus thunbergii) has also been researched.

The third research topic covering conservation and reproduction concerns a postglacial relic conifer species, Pinus parviflora, which is distributed in the Boso Hills. This was endangered but its native habitat and the individuals found there have been conserved and offspring have been propagated.

The University Forest has suffered severe damage from deer since the 1980s, with planted saplings and under-story vegetation being particularly affected. The increase in deer corresponds to an increase in the Haemadipsa zeylanica japonica population. This causes problems in research and education. So for the purpose of appropriate wildlife control for the protection of forest flora based on environmental capacity, research and experiments are undertaken.

Other important research topics are the study on rainfall runoff processes by a paired watershed approach and a study of the lifecycle of seedlings of Phyllostachys pubescens.

7. Social program

This University Forest holds social events such as summer schools for high school students, extra-curricular study for primary and junior high school students and open forest events for the public in spring and autumn.