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| White pine shelterwood near North Bay. |
A new journal article from OFRI’s Bill Parker and Tom Noland reports on white pine seed production following a seed cut, which is part of the uniform shelterwood silviculture system used in most of Ontario’s managed white pine stands. (A uniform shelterwood is a partial harvest in which trees are removed to create a uniformly spaced residual canopy to allow regeneration under moderate shade of the remaining trees.)
The journal article reveals that:
- The shelterwood harvest did not change total seed production.
- Variability in seed production was related mostly to stand structure, with more white pine seed produced where white pine basal area was higher.
- Using the uniform shelterwood system seed cut in second growth white pine stands (where residual pine basal area is greater than 12 square metres per hectare) did not reduce white pine seed production, seed quality, or potential for natural regeneration during a mast (high volume) seed year. (Scroll down to read more about mast years.)
Want to read more? Email OFRI and ask for a PDF of Comparative Mast Seed Production in Unmanaged and Shelterwood White Pine (Pinus strobus L.) Stands in Central Ontario.
To learn more about white pine, click on the button!
Did you know...? When foresters talk about mast, it’s nothing to do with boats!
- Mast is another word for tree seeds. It comes from the Old English word mæst, which referred to forest tree nuts that fell to the ground and were used to feed pigs.
- Many tree species show a pattern in how much seed they produce over time. A peak seed year—one in which trees in a given area produce many more seeds than usual—is known as a mast year. Scientists think one reason trees have mast years is to produce more seeds than predators (animals, insects) in the area can eat, helping to ensure a few seeds will survive to germinate and grow. Regionally synchronized flowering associated with mast seed years is also thought to improve pollination.
- How often mast years happen depends on the tree species. The triggers are not fully understood but include climatic cues and trees’ physiological condition. Late spring frosts, droughts (especially in the late summer or early fall), insects and disease, and other stressors can affect whether a mast year occurs.
