Forests as climate protec­tors – how trees can save the climate

Forests in Climate Change

We rely on forests – they give us timber, bind CO₂, store water, regulate tempe­ra­tures, provide habitats for many species – and are there­fore indis­pensable to us. We need them.

 

How well our forests can cope with climate change is influenced by the struc­ture of the forest.

 

Mixed deciduous forests: All-rounders in climate change

• Humus forma­tion: leaves and branches fall to the ground and are decom­posed by count­less organisms into fertile humus. In contrast to the litter layer in conife­rous forests, the soil is less acidic, which promotes the diver­sity of soil organisms.
• Cooling effect: leaves reflect sunlight and evapo­rate water through their leaves – this cools and lowers the ambient tempe­ra­ture, even on hot days. Broad­leaf trees cool more effec­tively than conifers.
• Water storage: broad­leaf mixed forests store rain better than conife­rous forests and thus protect against flooding and drying out. Some of the rain seeps into the ground­water, from which 90 % of our drinking water comes. Another part of the rain is evapo­rated by the broad­leaf trees, which leads to rain again elsewhere – thus stabi­li­sing the green water cycle.
• Biodi­ver­sity: broad­leaf mixed forests offer various struc­tures through diffe­rent tree species, deadwood, under­growth, leaves and humus, creating count­less niches for more birds, insects, fungi and mammals.
• Resili­ence: broad­leaf mixed forests with diffe­rent species are more stable against storms, drought and pests, because the risk of damage is redis­tri­buted across diffe­rent species and the balance of pests and benefi­cial organisms is improved by greater species diver­sity..

 

Monos­truc­tured conife­rous forests: high risk

Many of today’s forests were planted as commer­cial forests – often with non-native, fast-growing pines or spruces. These monocul­tures:

• are more suscep­tible to storm and drought damage as well as pests,
• have a lower water storage capacity,
• harbour fewer species
• and are there­fore less climate-resilient than broad­leaf mixed forests.

More than 40 % of German forests are monos­truc­tured conife­rous forests that are not native to their sites. If incre­asing droughts and damaging events, such as bark beetle infesta­tions, lead to their mass die-off, then conife­rous forests cease to be CO² sinks and suddenly become CO² emitters, as the carbon bound in wood, litter and soil is released again. This causes CO² emissions and further warming.

 

Climate-adapted forests

The forest of the future consists of diffe­rent tree species and is designed as a climate-resilient broad­leaf mixed forest. It is species-rich, and is managed as close to nature as possible, has humus-rich soils and can store rain very well.

 

Conclu­sion: Forests are not just a backdrop

Forests are active allies in climate change. Those who plant deciduous trees plant the future: through climate-resilient CO₂ binding and by streng­thening natural, living ecosys­tems.