There are various vegetation types in Japan due to latitudinal differences ranging from subtropical forests, warm temperate forests, cool temperate forests to sub-frigid forests respectively due to variety of climatic conditions.
Fig trees (Ficus microcarpa, Ficus superba), and Fan Palm (Livistona chinensis) are distributed in sub-tropic forests located south of Tokara Islands. Warm temperate forests are located from the western pacific coast to Kyushu island, which is dominated by Heaceae family, Persea thunbergii, Castanopsis cuspidata and some kind of Evergreen Oaks (Quercus gilva, Quercus myrsinaefolia. etc.). Cool temperate forests are located from the middle to north-east and dominated by Beech (Fugus crenata), Chestnut (Aesculus turbinata), Katsura tree (Cercidiphyllum japonicum), Deciduous Oaks (Quercus mongolica, etc.), Larch (Larix leptolepis), Firs (Abies firma, Abies homolepis), Hemlock (Tsuga sieboldii), Cedar (Cryptomeria japonica). Cypress (Chamaeryparis obtusa), Hiba (Thujopsis dolabrata), etc. Sub-frigid forests are located mainly in Hokkaido island and consist of Northern Fir (Abies sachalinensis) Northern Spruce (Picea jezoensis), Silver Fir (Abies veitchii), Northern Hemlock (Tsuga diversifolia), Birches (Betula maximowicziana etc.), Linden (Tilia japonica), Manchurian ash (Fraxinus mandshurica), etc. Major plantation species are Cedar, Cypress and Pine in most parts of Japan, however, Northern Fir and Northern Spruce are major species in Hokkaido.
As of the end of March 1995, total area of forests of Japan was 25,146 thousand ha (or 67% of the total land area of the country), of which artificial forests occupied 10,398 thousand ha, natural forests 13,382 thousand ha, and others 1,366 thousand ha1. Total growing stock was 3.5 billion m³, and it is growing annually by 70 million m3 without extraction, mainly in artificial forests established after the war.
1The various types of forest as a share of total forest cover in 1995 were: 41% plantations/artificial, 53% natural forests and the balance other types. Of the total area, nearly 58% were privately owned.
The artificial forests are gradually reaching the age of utilization, south-western forests in particular, but 70% of the total artificial forests are younger than 35 years, which still need tending and thinning.
In terms of ownership of forests, 14,572 thousand ha are private forests, 2,730 thousand ha are public forests and 7,844 thousand ha are the national forests, of which 7,647 thousand ha of the national forests is managed by an independent special account.
4.2.1 Forest diseases and harmful insects
4.2.2 Fire and weather disasters
Pine forests in Japan are precious, some for tidewater control and others as landscape forest; but they are suffering great damage, by pine nematode (Bursaphelenchus japonicus) which disturbs normal growth and the pine trees die eventually. The nematode is spread by the Japanese pine sawyer (Monochamus alternatus).
As a result of implementation of various protection operations (including extermination by cut and burn, spraying pesticide from the ground and from helicopters), the volume of damage by nematodes peaked in 1979 and has since declined with 920 thousand m3 of damage in 1996. However, the damage has not yet been contained completely, with total damage still high; furthermore, where damage has been suppressed down to the minimum forests may suffer further severe damage again due to weather factors or otherwise. Therefore, measures have been taken to deal in a holistic manner with any kind of forest disease and harmful insect correctly, including pine nematode as only one of many.
Meanwhile, measures have also been taken to deal with increased damage by wild animals, deer in particular.
Snow damage, wind damage and drought damage occur in Japan. Although the areas affected vary significantly by year, Table 1 shows the damaged areas in private forests in the last five years.
It is clear that with regard to forest fire, it is necessary to promote enlightening of the people.
Table 1: The damaged areas by fire and weather disasters 1991-1995 (ha)
|
Year |
Damage (by type of weather disaster) |
Fire damage |
|||||||
|
Total |
Wind |
Flood |
Snow |
Drought |
Freeze |
Stormy tide |
Others |
||
|
1991 |
78,773 |
70,444 |
292 |
5,886 |
231 |
335 |
1,585 |
- |
2,739 |
|
1992 |
5,831 |
1,759 |
118 |
2,956 |
712 |
283 |
3 |
- |
2,323 |
|
1993 |
17,503 |
12,162 |
914 |
3,275 |
416 |
702 |
34 |
- |
3,260 |
|
1994 |
17,821 |
251 |
40 |
732 |
16,046 |
752 |
- |
0 |
2,776 |
|
1995 |
5,874 |
1,142 |
389 |
1,757 |
2,234 |
352 |
- |
- |
2,016 |
Note: National forest is not included in weather disaster statistics.
