We measured the foliage area, weight and number of buds on young and mature balsam fir and white spruce trees. With these measurements total amounts of foliage per tree and per unit area of forest land can be calculated. These estimates can be used to determine the absolute numbers of insects feeding on these trees, numbers that are important in understanding patterns and fluctuations of population abundance. We also discovered that spruce budworm larvae occur preferentially in buds arranged in clusters.