black spruce is one of the most common commercial softwoods in northwestern ontario. its abundance, along with its physical and mechanical properties, make it a very important species for commercial harvesting. its physical and mechanical properties make it suitable for infrastructure and load-bearing purposes, and knowing how these characteristics can be maximized for the best quality lumber of important. the way trees are managed while they are growing affects what kind of mechanical properties they end up with when they are harvested, particularly in regard to thinning levels. this thesis examines the effects of light and heavy thinning on black spruce physical and mechanical properties, and which of the two produces the better properties, particularly for the purpose of wood quality. nine trees were taken from a forest near beardmore, ontario, where thinning treatments were applied. there were three different treatment types in total: light thinning, heavy thinning, and control. the trees were harvested after 15 years and cut into sticks, where they were tested for properties, including modulus of elasticity and modulus of rupture, according to the astm standards. the sticks were then cut into compression and density cubes and tested for compression parallel to grain and density also according to the corresponding standards. these tests were all done with the sticks and cubes at 12% moisture content. after the density measurements were taken, the density cubes were dried in an oven and tested for density again at 0% mc. data analysis was done using r studio and results found that light thinning produced the best physical and mechanical properties consistently compared to the heavy thinning and control plots.