Grasses growing under trees are subject to more than just shade stress. These grasses must compete with tree roots for soil space, water, oxygen, and nutrients. Tree roots may extend far from the canopy line (beyond the tree's actual branches and leaves), so these competitive effects can also occur at some distance from the tree. In some cases, removal of trees or trimming of lower branches may be necessary for continued grass growth. Decreased photosynthesis under lower light (shade) is directly related to a decrease in the biosynthesis of carbohydrates (sugars) essential for growth and health of turfgrass. Reduced sugar availability to support adequate growth can also exacerbate the negative impact of wear and other stresses on many turfgrass species because reserves are not available to support re-growth of damaged turf.