Summary # 7 How ecosystems change

Abandoned Farm- First year a comunity of crabgrass, insects and mice,
invades the field were corn once grew.

Second and third years ragweed, and tall grasses grow among the crabgrass. It can easily survive in the shade cast.

Four to Six Year Later The hot, dry field of tall weeds provides a perfect environment. More birds join the community.

Twenty five years later pine forest has replaced the old farm field.  Yet the number of new pine seedlings drops bacause they can´t grow in the shade.raccoons and foxes begin to visit.

One Hundred Years Later The forest is now mostly decidius trees. These trees are habitats of many different kind of animals.