Introduction:The typical definition of eutrophication is 'decrease in the levels of oxygen in the water bodies due to effects of excessive use of chemical fertilisers.' This statement clearly tells us all about the cause of the problem of eutrophication.
Oak is a common wood, yet many people arenât aware that there are two distinct species â red oak and white oak. Between the two, there are only subtle differences when it comes to durability, hardness, and cost. Color and grain pattern are the distinguishing features that set red oak and white oak apart.
The tans and browns of oaks are caused by tannins which accumulate as the chlorophyll disappears. Fall color starts in September with poison ivy and sumac and ends in November with the larches and weeping willows. Frost and freezing temperatures will stop the coloration process and blacken the leaves. Source: Barbara Larson, Extension Educator, Horticulture. Morton Arboretum: Why Leaves Change Color.