According to observations of naturalists and beekeepers.
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200 kilograms per ha
SOURCE FOR HONEY BEES:
Mountain maple is found throughout southeastern Canada and the northeastern United States, from Newfoundland to Saskatchewan south to Connecticut, Pennsylvania, Ohio, Michigan, northeastern Iowa, and in the mountains to western North Carolina and eastern Tennessee.
This plant is present in at least 32 states/provinces in this country.
Mountain maple is a native, deciduous tall shrub or small tree. In the Appalachian Mountains, the maximum height of mountain maple is 33 feet (10 m), but it is usually smaller. In the northern parts of its range, maximum height is 20 feet (6 m). Maximum d.b.h. is 6 to 8 inches (15-20 cm) in the Appalachian Mountains and rarely over 3 to 4 inches (8-10 cm) in the north. This tree has a short, often crooked trunk, with a shrubby or clumped growth form. The bark of mountain maple is drab and flaky or furrowed. The root system is shallow; the majority of the roots are close to the soil surface. The fruit is a two-winged samara.
Height growth averages approximately 1 foot (0.3 m) per year, with maximum growth occurring when plants are 5 to 10 years of age. Plants become decadent at around 40 to 50 years of age. Older mountain maples often produce more new vegetative growth than younger individuals.
Mountain maple flowers from May to June, after the leaves are fully developed. Fruit ripens from mid-September to mid-October.
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)