Tree terms: m
- m
 - M
 - M (apple rootstock)
 - macadam
 - macronutrient
 - made ground
 - MAGIC
 - Magistrates court
 - magnitude
 - maiden (forestry)
 - maiden (fruit tree)
 - main
 - main stem
 - main-stem diameter
 - main-stem volume
 - Malthus
 - mammals
 - Management of Health and Safety at Work Regulations 1999
 - manège
 - manhole
 - mansard roof
 - maquis
 - MArborA
 - market garden
 - marsh
 - marsh saxifrage
 - masonry
 - mass extinction
 - massaria disease of plane
 - mast
 - mast year
 - material consideration
 - matric water potential
 - matrix fence
 - matrix paving
 - mattock
 - maturity (tree parts)
 - maturity (whole tree)
 - maul
 - mead
 - meadow
 - mean annual increment
 - mechanical stress
 - mechanics
 - medieval
 - medieval gardens
 - medieval warm period
 - medullary ray
 - mega-
 - membrane
 - Men of the Trees
 - mens rea
 - meridional overturning circulation
 - meristem
 - mesh-protected turf
 - mesic
 - metabolism
 - metabolite
 - metalled
 - methane
 - methane clathrate
 - method statement
 - metre
 - metric system
 - Metriguard
 - MEWI
 - MEWP
 - MH
 - microclimate
 - microfibril
 - micro-injection
 - micronutrient
 - microsite
 - microspecies
 - microtunnelling
 - middle lamella
 - midge
 - Milankovitch cycles
 - mildew
 - millennium green
 - Millennium seed bank
 - millennium yew
 - milli-
 - minarette
 - mire
 - Miscanthus (M. ×giganteus)
 - mist
 - mistletoe
 - mite
 - mitigate
 - mitigation banking (ecosystem banking)
 - MM
 - mobile elevating work platform
 - modern and post-modern gardens
 - modified Lorette system
 - modified plasticity index
 - modulus of elasticity
 - Mohr-Coulomb’s law
 - moisture content
 - mole drain
 - moling
 - moment
 - Monocotyledoneae
 - monoecious
 - monolith
 - moor
 - mor
 - moribund
 - mortar
 - mortice
 - mosses
 - moths
 - mounding
 - mountain
 - mountain pine beetle (Dendroctonus ponderosae)
 - mouse-ear
 - movement joint
 - mowing strip
 - mulch
 - mull
 - Multi-agency geographic information for the countryside (MAGIC)
 - multi-size pavers
 - multi-stem
 - muntjac deer (Muntiacus reevesi)
 - mushroom
 - mycelium
 - mycorrhiza