What kind of growth does Reaction Wood consist of in trees?

Reaction wood is a specialized type of wood that develops in response to mechanical stress, such as leaning trees or the weight of heavy branches. This growth is an adaptive mechanism that helps the tree maintain stability and restore equilibrium by reinforcing structural integrity.

When a tree experiences external forces or imbalances, it produces reaction wood to counteract that stress. In hardwoods, this typically manifests as tension wood, which forms on the upper side of the lean; in softwoods, it appears as compression wood, forming on the lower side. This growth is denser and changes the wood's properties, allowing the tree to better support itself under duress.

Other types of wood growth, such as those mentioned in the other options, do not involve this adaptive response to mechanical stress. Therefore, the characteristic nature of reaction wood clearly differentiates it as a growth type that is specifically a response to external mechanical forces rather than normal growth patterns, seasonal dormancy effects, or root growth.