Can we save forests under a changing climate?

Human activities have brought about a destabilising era of climate change, threatening the continuity of life on our otherwise stable planet. The climatic conditions that support life on Earth are rapidly changing, and the future is uncertain.

Forests play a crucial role in regulating the Earth’s temperature and moisture, thereby promoting ambient conditions that support life. However, forests themselves are vulnerable to the negative impacts of a changing climate, and their active management is necessary to preserve them.

Designing a response to meet an unforeseen future is risky and often avoidable. However, taking no action is not an option either. So, what action should be taken, and on what basis? Can this dilemma be resolved by adopting a ‘no-regrets approach’ to forest management? Perhaps yes, especially since no alternative guidance is available in this regard and taking no action would be irresponsible.

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The ‘no-regrets approach’ to forest management involves initiating management practices in anticipation of an expected future and relies on precautionary principles to minimise the risks. Under a warmer world, while larger climatic trends are known, the occurrence of climatic events remains uncertain in space and time. In such a situation, the ‘no-regrets approach’ involves enhancing the resilience of forests, managing non-climatic stresses on forests, and adopting anticipatory adaptation measures by recognising the expected climatic patterns in the region.

Risk to forests: The presence of a forest at a location, and its nature, depends on the soil and climatic factors such as sunlight, moisture, and temperature. Under a changing climate, the factors of sunlight, moisture and temperature are changing. Model-based projections for Indian forests suggest unfavourable or sub-optimal climatic conditions for at least a third of forests at their current location in the medium (2050s) to long term (2080s). Vulnerability assessments suggest a higher vulnerability of drier forests under future climate.

Soils provide nutrition to forests and moisture is necessary for synthesising food. However, in a warmer world, soil is subject to loss and degradation, and moisture distribution is projected to change. Warmer temperatures can rapidly cause depletion of organic matter in the soil if the rate of replenishment of organic matter slows down due to drought and the lower productivity of forests. This can potentially result in degraded soil structure and desertification. Rapid soil loss can occur from drought and wind-blows, and high-intensity rainfall and water flow. Reduced availability of soil-moisture and extended droughts can lead to inadequate regeneration and forest dieback. These threats to forests under future climate are well documented in the literature.

Moreover, forest fires can cause grave injury to forests. Forest fires are man-made in India. With ambient temperatures warming, fire incidences are likely to increase and impair conservation efforts. Further, the risks to forests from pestilence and disrupted pollination cycles are complex to understand, and knowledge to manage them is lacking.

It is also necessary to recognise the risks to forests that arise from anthropogenic sources. The combined effect of climatic and anthropogenic factors on forests is often multiplicative and not additive. The saving grace, however, is that the anthropogenic sources of risk can be managed, and active management can help the forests respond to at least a limited change, say up to 1.5 or 2 degrees centigrade global warming.

Global initiatives like the United Nations Forest Forum (UNFF) and the Convention on Biological Diversity (CBD) recognise the risks to forests in a warmer world. Generally, the strategies to deal with the risks hinge on the protection, conservation, and enhancement of forests and forest habitats in partnership with the local communities and other stakeholders.

‘No-regrets’ management: Human action cannot match the speed and scale at which climate change impacts can occur. Nonetheless, global agencies like the UN Food and Agriculture Organization (FAO) and UNFF recommend that active forest management can help them adapt and sustain.

Forests are non-portable, they sustain or perish at a location. However, forests can migrate along suitable climate gradients or hop to safe refugees on the migration path. Such hoping and migration are an outcome of regeneration at locations where the conditions for growth supported by soil and moisture prevail.

Strengthening the forest site conditions by conservation of soil and moisture is thus clearly a robust strategy. This together with measures like conserving remnant old-growth forests and trees, planting leguminous trees, protecting the corridors along the favourable climate gradients, managing anthropogenic disturbances to forests, and promoting vegetation along fences, rivers and streams across the landscape can help forests survive.

To cover large forest landscapes under climate change-necessitated management, the response should be essentially designed as a hub-and-spoke type of network of locations that enhance the probability of sustenance of forests at the present locations, and forest regeneration at fresh locations where favourable factors of growth are anticipated. Fresh locations are identified in the zones species are projected to occur under future climate by the climate-vegetation models. This is visualized as a honeycombing of the landscape by hubs where appropriate species are planted and linked by man-made (say, live fences) or natural (say, streams) corridors (spokes) between existing and new forest sites.

The management response in the case of existing forests is proposed around soil-moisture conservation, as it is understood to strengthen forest resilience through higher biological activity and growth. Better soil capacity and moisture availability helps to deal with droughts and avoids the possibility of maladaptation in case the action is species-centred. Additionally, the higher capacity of soil to hold water and improved stream flows can help forest as well as human society. Accordingly, it is proposed to dig water-trapping trenches, erect check dams, and dibble seeds of native species in/on/around them in forest areas.

The measures suggested above are useful for strengthening the resilience and adaptability of the forests, with or without climate change. Following this approach, the possibility of maladaptation is avoided. Changes more catastrophic than what highly resilient forests can withstand, would in any case be beyond our management capabilities. While ‘no action taken’ is not an option and would certainly be regretted, undertaking the above actions would at least soothe the regrets, at worst as unsuccessful management.

Finally, it is desirable that professional foresters consider, differ, and further evolve the proposed approach.

(Ther writer is a member of Indian Forest Service, Karnataka Cadre)