Published in `Proceedings of WWF China Programme International Workshop `Tibet's Biodiversity: Conservation and Management, Lhasa September 1998'. China Forestry Publishing House, Beijing, p.62-67 [submitted for publication 1999]
Major Threats to Tibetan Forest Ecosystems and Strategies for Forest Biodiversity Conservation
In the summer of 1998 the condition of the forests of the Tibetan prefectures of W-Sichuan, NW-Yunnan and along the upper Yangtze River (Jinsha Jiang/Dri Chu) in Tibet Autonomous Region (TAR) finally received national and international attention. While fighting the disastrous floods downstream, deforestation in the upper catchments of the Yangtze has been recognized as the main cause. According to Chinese government authorities as of September 1st all logging has to be ceased and loggers will be retrained as tree planters to restore deforested slopes.
This paper will focus on the major threats to Tibetan forest ecosystems, and possible strategies for conservation. Forest ecosystems are a prerequisite for forest biodiversity conservation. Much of the remaining forests are primary forest, rich in biodiversity. The main threat is the extensive rapid loss of forest area. Biodiversity loss through mono-species timber forests is now a minor problem. However, this may soon change, especially in the highly biodiverse and very productive subtropical and warm-temperate forest zones, where intensive timber production could be profitable..
Forest ecosystems and geo-ecology
Forested areas are common on river valley slopes of the south-eastern Tibetan Plateau. In TAR presently 71,459km2 (5.7% of the area) are classified as forest area, however only 39,792km2 (3.2%) are under forest cover (Tibet Land Use 1992). In W-Sichuan 119,740 km2 (41%) are classified as forest land, but only 42,130km2 (14.38%) are `well-stocked' forested land (Yang 1987). Between June and September, the most favourable growth season, the summer monsoon moves up along the river valleys onto the Plateau bringing in >80% of the annual precipitation. From the deeply dissected southeastern fringe (precipitation >1,500mm/a) a striking decrease in precipitation and temperature occurs towards the northwestern plateau (<100mm/a). This gradient is matched by a corresponding decrease in biomass production and biodiversity. Forest ecosystems in Tibet (i.e. juniper forests) manage to survive with a precipitation level below 500mm/a and an annual average temperature as low as 0ºC.
Extreme altitudinal variations promote high biodiversity. Vegetation composition shows clear altitudinal and expositional distribution patterns, reflecting a multitude of climatic site conditions [see Fig.1]. 75% of the documented vascular plants (9000 species in 1500 genera) found in the Chinese administrated area of the Plateau, grow in the forest region (Li 1995). In TAR 90% of the approx. 6000 species are distributed in the forest region. The flora is rich in endemics (955 species). However, only 4 genera are endemic, reflecting the recent geological uplift of the plateau, which did not leave enough time for the development of new genera or families. Not surprisingly the southeastern plateau has been known since the early 1910s as being rich in species diversity and is currently recognized by WWF and others as a global biodiversity conservation region of the highest priority.
The Southeast contains pockets of extremely biodiverse tropical rain forests consisting of Terminalia, Shorea, Ficus, (among other tree species) in deep valleys below 1100m characterized by average temperatures >20ºC. Slopes below 1800m - 2600m are commonly covered by subtropical evergreen-broadleaved forests (>800mm/a, 12º-20ºC), which are dominated by members of the Fagaceae (i.e. Castanopsis, Lithocarpus), Lauraceae and Theaceae. In drier or disturbed subtropical sites, but mostly warm-temperate locations reaching 3500m, pine forests (Pinus densata, P. yunnanensis, P. griffithii and P. roxburghii) are widespread. Sclerophyllous oak forests (Quercus sect. semecarpifolia) are also common on south-facing slopes of these areas. The warm-temperate montane mixed forest often has a strong spruce-fir (Abies-Picea) element. Moist sites are under hemlock (Tsuga dumosa) dominated mixed forests.
The cold-temperate forest ecosystem is dominated by a great variety of conifers, mostly spruce (i.e. Picea balfouriana, P. likiangensis, P. asperata, P. purpurea, P. smithiana, P. spectabilis), fir (i.e.Abies squamata, A. georgei, A. spectabilis, A. faxoniana), juniper (i.e. Juniperus tibetica, J. saltuaria, J. wallichiana) and larch (Larix griffithiana, L. himalaica, L. potaninii, L. mastersiana), often with an admixture of birch (i.e. Betula utilis, B. platyphylla, B. albo-sinensis) and poplar (i.e. Populus davidiana, P. rotundifolia). Spruce-fir forests are the most widespread forest ecosystem [Fig.2]. Exposed and degraded sites are often under juniper forests, which form the ecotones between forest and grassland ecosystems. Juniper and spruce forests often form grassland-forest mosaics which most commonly are a cultural landscape [Fig.3]. The treeline may extend to 4700m, the highest in the world. For example, in Riwoqe (Pinyin: Leiwuqi) County (Qamdo Prefecture, TAR) a last stand of south slope junipers can be observed at the Dzekri La Pass at 4600m.
The forests of the Tibetan Plateau are of the greatest importance to regional and international water regimes. Nearly a billion people live downstream in the basins of Yangtze, Yellow River, Mekong, Salween and Tsangpo-Brahmaputra, all originating on the plateau. In recent decades the forests were considered primarily as a source of timber. For many local administrations the timber industry is their most important source of cash revenue. All too often the hydrological functions of these forests has been severely compromised and disregarded. Water retention capacity in a primary forest is a multiple of retention in clearcuts or degraded forest. Yang (1986) documented that the evaporation rate on clearcuts is 3.8 times higher than in forests and water run-off more than double in W-Sichuan coniferous forests. On clearcuts run-off maximum occurs 1.5h after precipitation as compared to 11h later under forest cover. The altered run-off causes intensified erosion with higher silt content and thus the probability of flooding increases. Reduced water retention and quicker evaporation also cause reduced run-off after the rainy season, thereby reducing water run-off in the dry season.
Furthermore, the forests' immense biodiversity contains a great variety of genetic resources which need to be protected for the future. Invaluable genetic information is contained in Tibetan species regarding successful adaptations to cold, extreme diurnal temperature changes and intense high altitude insolation. The forests are an important source for medical plants, edible mushrooms and animal by-products. However, unchecked over-harvesting is a threat to species in high demand and organisms living in association or symbiosis.
Major threats to forest ecosystems on the Tibetan Plateau
Forest ecosystems are on the decline on the Plateau. There are several causes ranging from plateau uplift and fluctuations in global climatic patterns to human impact. In this paper only human impact will be discussed, which can be traced back to the Neolithic era in Tibet. However, ecological conditions are an important factor regarding the extent and permanence of human impact. For example, in climatic more continental areas with drier and colder conditions, forest ecosystems have more obstacles to regenerating following human impact and thus deforestation is relatively quickly accomplished. In moister and warmer areas, more conducive to forest growth, forest self-regeneration is more successful. Thus the loss of forest areas is not as dramatic as in the more continental areas, where it is evident that wide areas are a man-made landscape.
Grazing and agriculture
Through the millennia Tibetans and other indigenous ethnic groups have developed valid strategies for survival. While archeological findings [i.e. Karub (Karou) near Qamdo dating back to 5000a BP (Huang 1994)] indicate a strong reliance on wildlife, wildlife has gradually been replaced by livestock. Also potential wildlife forest habitat has been replaced by pastures and agricultural areas in favorable valleys. Pastoralism, the backbone of traditional subsistence production in Tibet has clearly reduced forest cover. Herdsmen have turned extensive forest areas into pastures, which have been preferred over forests, be it intentionally through burning or as a welcome by-product of continuous grazing or wood extraction. Forest grazing and slope burning (mostly applied for clearing shrubs at present) is still a common practice. In the forest region most south slope pastures below treeline were covered with trees (see Winkler 1998a). Furthermore the recent economic liberalization poses new risks: i.e. an increase of livestock production for newly created markets is placing more pressure on grazed forests.
Firewood and local timber consumption
Forests are an important source of firewood and construction timber for local consumption, which has been quantified in NW-Yunnan as 1.7m3/a per person (Li 1993). Forest destruction and degradation is a common sight around settlements. Traditional practices are often not sustainable. For example, in an area recently depleted of mature trees in Dengqen County I observed a local man transporting many freshly cut young spruces (Ø<10cm), although other shrubs were available too. In Riwoqe and Dege County mature healthy conifers are often felled for firewood, while smaller trees (Ø 20-40cm) are preferred for construction, since they are transportable without machinery. Big trees are being cut into transportable smaller pieces [Fig.4] on site. People also frequently cut the tops off small junipers, thus keeping them in shrub form instead of only cutting branches. Furthermore, tree planting is not part of traditional landuse practices.
In the northern part of the forest region wide forest areas have been lost completely. Data on the amount of present forest distribution versus potential distribution is not available. Future investigation using GIS could provide data. However, my own observations (1997 and 1998) along the northern route of the Sichuan-Tibet Highway and in its hinterland clearly indicate extensive and historical forest reduction. In many counties (i.e. Ganzi and Dege, W-Sichuan and Jomda, Qamdo and Riwoqe in TAR) historical deforestation is estimated at 30% to 60% while in counties west of Riwoqe (i.e. Dengqen and Baqen) forest area reduction is estimated at greater than 80% [Fig.5].
As for most forest ecosystems on earth the main threat presently comes from logging. Increasing demand for timber in connection with the exhaustion of resources in more easily accessible areas leads to exploitation of more remote areas, where existing forestry regulations are often not fully implemented due to difficult communications. Although official TAR figures imply that current cutting rates are sustainable, a closer look reveals that sustainability is often not achieved. Riwoqe County, visited in 1997 while conducting a feasibility study for a sustainable forestry project, will be presented as an example of the current forest industry situation in TAR. Riwoqe's forest area comprises 103,163ha and should contain a standing volume of around 26,000,000m3, based on the prefectural average volume (256.3m3/ha). In 1997 the official annual cut was 8000m3, filled by ca.300 year old Picea balfouriana. This cut seems negligible. However, a closer look reveals some of the typical problems. Wasteful logging was evident and logging efficiency in W-Sichuan is reported at 40% (Li 1993), indicating that 20,000m3 need to be felled to fill the cut. This requires clear-cutting between 30-80ha, depending on stand volume. Furthermore, local non-commercial consumption (see above) is approximately 65,000m3/a, thus suggesting a total extraction of 85,000m3, excluding losses to fire, disease and illegal felling. 85,000m3 represents 0.33% of the growing stock, which theoretically meets the requirement of sustainable harvest.
However, natural decay needs to be accounted for as well. In a natural forest ecosystem decay equals increment. Furthermore, sustainability is based on forest regeneration, but successful reforestation is seriously lacking [Fig.6]. For decades the forest department relied mainly on natural regeneration, an approach which produced unsatisfying results due to intruding livestock. Prefectural regulations from the early 1990s required reforestation of 7ha/a, which Riwoqe attempted to fulfill for the first time in 1997 with imported seedlings. Still 7ha is only a fraction of the felled area. Newest TAR regulations require reforestation of the whole impacted area. However, funds and the necessary infrastructure such as functioning nurseries and trained personnel are often lacking. In brief, present forestry practices still lack sustainability. Figures available leave the impression of sustainable practices in TAR, but the reality is a further accelerated rate of deforestation. Statistics for Sichuan's Tibetan prefectures, where over-harvesting for the past 45 years reached more devastating dimensions, indicate a loss of more than 50% of the forest area with negligible reforestation (Li 1993, Yang 1986). A state timber quota system which is being faded out prescribed irresponsible timber extraction (see Winkler 1998a). Hopefully with the logging ban and the reforestation program the mismanagement is being stopped in the Yangtze catchment area. However, there is the risk that the logging activity will be moved into other Tibetan watersheds, such as the Mekong, Salween or Tsangpo.
Possible strategies for conservation.
For successful protection of forest ecosystems and their biodiversity a two pronged approach is needed. Key forest ecosystems must receive effective protection (i.e. Tsangpo bend) and unprotected forests need to be managed sustainably, thus guaranteeing that the forest area will not be further reduced or degraded.
Key areas with high, unique and/or representative biodiversity should be identified and mapped. TAR already has several forest preserves (see listing in this volume). However, some of them are quite small and it seems advantageous to enlarge them. Clearly missing is a representative preserve in the cold-temperate forests of Qamdo prefecture and a larger preserve in the `Three Great River' area in TAR's SE corner. In some cases conservation areas could be established which contain fully protected core areas besides sustainably managed timber forests, which could financially support conservation, since funding is a major limitation for conservation in Tibet.
Sustainable practices need to be introduced for traditional resource management and for the timber industry. Forestry, just as tourism (another possible source for financing conservation), is regarded as a `pillar industry' for the future development of TAR. An integration of development and conservation is needed. Existing forestry laws are excellent, however weak implementation makes them ineffective. To the author's best knowledge, an overall forest management plan is still lacking. Short term gains need to give way to long term planning. The timber industry's management practices must be based on ecological principles with a minimum of negative ecological impact (i.e. selective cutting versus clear-cutting). The silvicultural management systems need to be modeled as closely as possible after ecosystem specific parameters. There is a long history of sustainable management of spruce-fir forests in the European Alps and elsewhere which might be successfully applied with necessary modifications in Tibet.
TAR has achieved impressive results in river valley afforestation with poplars and willows. The availability of this timber is easing local pressure on natural forests. However, these achievements do not directly address the loss of primary forests and the lack of sufficient reforestation of coniferous forests. Regeneration, as too often the case in the past, can not be left to nature alone. Reforestation efforts need to be increased dramatically. TAR needs to become self-sufficient in seedling production, all forest departments should have functioning nurseries. Also community and/or privately operated nurseries should be established. It has to be taken into account that reforestation will interfere with livestock grazing.
The most challenging issue will be the reversal of shortsighted traditional forestry practices. Less destructive methods need to be developed. Many practices cause forest degradation and accept deforestation as the final result due to a lack of alternatives or as means of extending pasturelands. Firewood consumption could be reduced by energy efficient fireplaces. Firewood collection causes unnecessary harm to vegetation. Extension programs have to be implemented immediately to integrate local people in forest management and ensure sustainable production of fire and construction wood. The principle and the benefits of sustainability should be clear to all stakeholders. Local people need to understand the multiple benefits of sustainable forestry practices and reach a greater awareness of the importance of these forests to their lives. Conservation education designed to address local conditions should be included in all school curricula. Successful local programs need to be shared and implemented at greater scale.
However, it is not enough to educate locals. Most crucial is that local people have tangible benefits from conservation and reforestation, such as income opportunities and guaranteed rights of use. Presently nearly all forests are government owned and timber extraction for private use requires permits. Under the current system locals often have difficulties to see forests as their asset. Guaranteed rights might change the attitude. Households and villages should also be encouraged and supported to grow trees and manage forests, a practice applied in other regions of China, since the introduction of the `household responsibility system' with the economic reforms in the 80s. We should make use of already existing institutions like village councils, village leaders and forest guards. In addition the introduction of true participatory processes will help secure successful implementation fostering the process of making local people the stewards of the forests. More emphasis needs to be placed on incentives rather than enforcement. For example I was told in Riwoqe that the monasteries are forbidden to burn `shukpa' (juniper), a religious practice performed daily by almost every monastery and household. It seems more productive to require monasteries and households to actively engage in raising trees to fulfill their needs. Conservation which deprives locals of `their' resources will not succeed without intense policing and will make conservation appear as an enemy in the daily struggle for survival. On the contrary, conservation which recognizes peoples needs and actively engages in addressing resource shortages and offers solutions is much more likely to succeed.
Although extensive areas of Tibet's forests have been lost, impressive biologically diverse old-growth forests are still present. Preserving this heritage of global importance is a challenge but one that is attainable if executed in a spirit of mutual cooperation and respect. The present momentum gained by national and international attention to the state of Tibetan forests in relation to the recent devastating floods along the Yangtze can hopefully be channeled to improving forest conservation practices on the Tibetan plateau. The logging ban will hardly be the answer. Forestry is too important an industry, it is one of the very few economic opportunities in China's poorest region. However, it is very helpful to draw a line under past mismanagement and work on a sustainable solution with a strong conservation element, balancing ecology and economy for the benefit of all downstream and headwater communities.
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Fig.1: Spatial zonation of the forest vegetation of Jiuzhaigou (Zitsa Degu) Nature Preserve, NW-Sichuan. The forest-free patches on the south-facing slope are anthropogenic pastures (see Winkler 1998b).
Fig.2: Pristine spruce forest (Picea balfouriana, 4100m) near Yiri, Riwoqe County, (July 4th, 1997; Photo: D.Winkler).
Fig.3: Forest-grassland mosaic around Yiri (3950m, Riwoqe County). The forest area is being reduced gradually by local wood extraction and pasture creation. South slope spruce forests are often degraded. Junipers (in the foreground to the left), shrubs and pasture now dominate these degraded sites. Traces of forest fires are common (July 4th, 1997; Photo: D.Winkler).
Fig:4: Yaks carrying firewood up to the deforested summer grazing grounds. (Riwoqe, 4050m, July 3rd, 1997; Photo: D.Winkler).
Fig.5: Last forest above Gyangon (3900m), Dengqen County, in an otherwise nearly completely deforested valley (June 28th, 1997; Photo: D.Winkler).
Fig.6: Slope above Riwoqe town (Ratsaka) without traces of reforestation and very little natural regeneration. The former spruce forest slope is now used for grazing. (3980m, June 29th, 1997; Photo: D.Winkler).