white alder alnus incana in spring

absorb advance agroforestry alder alnus arboriculture assimilation bacterium bare buds bulbil coppice cover creeper dendrology eatage feeding forest forestry gray grey growth growths hoary incana legume low management microorganisms nitrogen nodule north nutrition open orange plant plants rhizobium root roots science second shoot silvics silviculture speckled spring timber tree trees tubercle undergrowth understory weeping wood woody young