M

Macronutrient – A chemical element necessary in large amounts (usually 50 mg/kg in the plant) for the growth of plants. Includes C, H, O, N, P, K, Ca, Mg and S. Contrast with micronutrient.

Mature Trees – Trees that have reached at least 75% of their typical final height and spread.

Meristem – Embryonic or undifferentiated tissue, capable of active cell division and differentiation into specialized tissues.

Micro-nutrient – A chemical element necessary in only extremely small amounts (less than 50mg/kg in the plant) for the growth of plants. Examples include B, Cl, Cu, Fe, Mn, Zn and Ni. Contrast with macronutrient.

Mulch – Any material such as stray, sawdust, leaves, plastic film,, and loose soil that is spread on the surface of the soil to protect the soil and plant roots from the effects of raindrops, soil crusting, freezing, and evaporation

Mycorrhizae – Beneficial fungi that provide water and nutrients to roots and receive carbohydrates from roots.