Windsail Reduction can help preserve a tall and healthy tree and prevent it from toppling over. Trees in the Pacific Northwest have extremely shallow root systems (and no tap root) due to the hard pan (or glacial silt) deposited here millions of years ago. Tree roots only descend about 3-4 feet in most circumstances. The tops of trees, an area known as windsail, can get very thick and busy. During the fall, heavy rain loosens the soil at the base of the tree. If windstorm occurs shortly after a heavy rain and a heavy gust hits the windsail, the entire tree can be taken down in an instant.