Ecosystems: Boreal Woodlands

Ecosystems: Boreal Woodlands

Introduction

Boreal forests are concentrated around the northern cap of the globe and represent 29% of the global area covered by forest. Contribute significantly to determining the global climate of the earth and the percentage of CO2 in the atmosphere and, like the rest of the forest, are invaluable in ensuring biodiversity. They constitute the largest reservoir of carbon in organic form alive on the planet, stored mainly in soil and litter.

Boreal forests form a homogeneous green belt circumpolar in which temperature is the environmental factor that contributes to determine the geographic boundaries. The northern and southern correspond to the isotherms of 13 and 18 º C in July, respectively, which implies that boreal forests are within the borders of Russia, Canada, Alaska and the Scandinavian countries Sweden, Norway and Finland. It is estimated that these forests cover an area around 920 million hectares. Despite its importance, its special features are often not well understood

Discussion

The boreal zone is often divided into three regions: maritime, continental and norcontinental, of which the second is the longest. In the maritime sub-area variation in temperatures throughout the year is relatively mild and winter is generally mild and cool summer, the average temperature of the warmest month varies from 10 to 15 ° C and the coldest month of 2 at -3 ° C.

The sub continent has long cold winters with heavy snow for 5 to 7 months, the average monthly temperature varies greatly, especially in the winter in the north, the dry wind and temperatures of -20 ° C to -40 ° C can become fatal to the trees, the mean temperature of the hottest month varies between 10 and 20 ° C.

Norcontinental subarea comprising the territories of Eastern Siberia and the Far East. It has a very long winter, extremely cold and dry spring occurs suddenly and the summer is short and relatively warm, although it may freeze at night, even in summer. The average temperature is between -7 and -10 ° C. The monthly average temperature can vary by more than 40 ° C and a low of -50 to -60 ° C, while the average temperature of the coldest reaches to be less than -25 ° C.

The climate in coniferous woodlands is a cool temperate or cold continental climate, depending on the proximity of the ocean. Rainfall is low, at less than 500 mm/20 in per year, with no significant seasonal pattern. Snowfall is frequent in winter, and frosts sometimes occur in summer. Summer temperatures reach a maximum of 10-15°C/50-59°F, while winter temperatures often remain below freezing, often as low as -10°C/14°F, for up to six months. The growing season is limited to six to eight months, but the long hours of daylight in summer (16-20 hours) allow the trees to photosynthesise sufficiently. The species composition in the boreal forest ecosystem is constantly changing. The basic principles of the dynamics of boreal species are illustrated by the natural succession of settlers stands, which dominate the deciduous species, birch, alder, ...