What is a timberline?

Some mountains have trees growing clear to their tops, but on many high mountains there is a line above which trees stop growing.

The place where trees stop growing is called the “timberline”.  Trees don’t grow above it because they cannot survive the freezing temperatures there.

Above the timberline the mountainside is likely to be a cold desert with only patches of lichens, moss and stunted vegetation twisted by the strong winds of the mountain tops.

Here, the bitter cold keeps the water in the ground frozen for much of the year, and bigger plants cannot get enough water.

Just  below the timberline the tall pine forests stand alone.  There tough, needle-shaped leaves can withstand the icy winds and harsh living conditions on the cold mountainside better than the broad-leaf trees can.

The timberline is much higher on some mountains than on others.  It depends on the climate, and latitude.

What is a rain forest?

A rain forest is a very dense and dark forest that grows in a land where the rainfall is very heavy.  A rain forest is a large, very thick forest in a land where rain is very heavy throughout the year.  The closely crowded trees need at least 80, and often much more, inches of rain each year.

Rainforest

Most rain forests grow near the equator.  Here it is warm all year round, and rain falls nearly every day.  The tall trees raise their leafy branches high above the ground.  The leaves are usually so crowded that little sunlight can filter through, and the forest is often dark.

The heavy rains wash much of the plant food from the surface soil.  As a result, the floor of a rain forest is often bare because smaller plants cannot grow in the dim light and poor soil.  Many people think of rain forests is jungles.

Jungle differs from tropical rain forests.  A dense carpeting of creepers, vines and undergrowth generally covers the ground in a jungle.  Some jungles have a few trees.  Dense jungles may grow in dry climates where rain forests can’t.  Jungles are among the least livable places on earth.  Poisonous plants, snakes and wild creatures live in them. – Dick Rogers

Climate change seen helping short-lived creatures

OSLO (Reuters) — Climate change is likely to disrupt food chains by favoring animals with short lifespans over often bigger rivals that are worse at tolerating temperature swings, scientists said. The researchers in Germany and Canada said that studies of the physical characteristics of animals showed that all have widely differing "thermal windows" — a range of temperatures in which they best feed, grow and reproduce.

That meant that climate change would not affect all equally.

"Climate change will favor species with wide thermal windows, short life spans, and a large pool amongst its population," the journal said of the findings. Big fish such as cod, which have narrow thermal windows, were moving north in the Atlantic, for instance, partly because the food chain was disrupted by a shift to smaller plankton, reducing the amount of prey on which large fish can feed.

A shift to smaller plankton meant that juvenile cod in the Atlantic had to use more energy to feed, slowing their growth. Female cod tolerate only a narrow "thermal window" when they produce eggs, part of a strategy evolved to cut energy use. The study focused on the oceans but the scientists said the findings may also apply to land creatures.

"Each species covers a certain range. The ranges overlap, but their (thermal) windows are not the same," Hans Poertner, of the Alfred Wegener Institute for Polar and Marine Research, who was one of the authors, told Reuters. Knowledge of the differences could help predict the reactions to climate change, widely blamed on human emissions of greenhouse gases from burning fossil fuels.

In the German Wadden Sea, larger eelpout fish, a long and thin species that grows up to about 500 grammes (1 lb), suffered more quickly than smaller specimens when summer temperatures rose above normal.

"In the Japan Sea, different thermal windows between sardines and anchovies ... caused a regime shift to anchovies in the late 1990s," they wrote. Source: ENN