Temperate Forests - Threats

One of the biggest threats to temperate forests is the human population. Yet, people have been recognising these threats over the years and started to act to conserve these beautiful biomes. A great success story where forests were saved from further destruction was from acid rain. In the 1980s acid rain was considered to be a major problem since pollution from the combustion of fossil fuel (SO_x, NO_x) from one part of the world (Great Britain) could have an effect on another one (Southern Scandinavia). Forests where left naked, with polluted lakes and very little life (Figure 1). Since then, governments and bodies have been trying to reduce the effect by limiting the pollution to different standards set over this time. In 2000 the sulphur emission was reduced from 6 million (1970) to 1 million (YPTE), but further work needs to be done to engage more countries for this cause.

Figure 1: Damage by Acid Rain (YPTE)

With the settlement of people the hunger for development has been a primary cause for the shrinking of these forests. They are ideal for the expansion of population and for agriculture due to the climate and the nutrient rich soil (marietta).

Logging is another threat to this biome due to the slow growing conifers that thrive there in addition to the decreasing populations of species due to fragmentation. The biological hotspot of the temperate forest of Chile is an example whereby fragmentation by logging could decrease biodiversity (Echeverría C. et al., 2007).

Global warming is a threat that will grow bigger if mode drastic measures are taken to decrease the effect. New research suggests that there will be more frequent heat waves in the mid-latitudes (Tang Q. et al., 2013) and with the release of the new IPCC report where the warming since 1950 is extremely likely to be caused by humans and where by it is projected that in some scenarios the increase in global temperature could exceed 2.0°C by the end of the 21st century is alarming. Lindner M. et al (2008) suggest that with the increasing climatic changes the vulnerability of the forests increases as well. Regional decline in productivity is expected for the Mediterranean due to estimated increase in fires and drought. The winter season is the pest control, but with the increasing temperatures the pests are not controlled leading to catastrophic effects for the forests (Figure 2). An example is the Scots pine (Pinus sylvestris L.) found in Europe that is attacked by the Thaumetopoea pityocampa moth (HódarJ. A. et al., 2003).

Figure 2: Reddish and brownish trees in this forest in Montana have been killed by the mountain pine beetle. The beetle population has soared in part because temperatures no longer plunge as low in the winter, so fewer get killed off (nytimes-green).

Invasive species could act as a threat to temperate forests. With the need to decrease the carbon in the atmosphere wrong management could lead to destruction. Inappropriate plantation of trees could result in decreasing biodiversity such as for some cases alien species of eucalyptus and pine (ecomii).

Temperate forests are supporters of human well-being, but humans have been imposing great threat either directly through logging or indirectly through climate change in addition to exacerbating some of the ‘naturel threats’ of pests. In two blog posts time I will be discussing some of the actions taken to limit and control some of these threats to Temperate forests and Boreal forest. Next post Boreal forest and the ecosystem services they provide.