Male cones shed pollen then wither and fall away.įertilization takes place one year after pollination. Pollination takes place over a 2 or 3 day period in late May or early June. They are usually in the upper part of the crown but may be on any crown branch that receives full sunlight. ![]() They are borne usually in clusters of 2 or 3 near the tip of the new shoots. Female cones at the time of pollination are ¼ ″ long conelets. They are borne in clusters on older branches in the lower part of the crown at the base of the new shoots. Pollen (male) cones are cylindrical, 5 ⁄ 16 ″ to ½ ″ long, and yellow or pale pink, yellow when shedding pollen. Male and female cones are borne on the same tree. The needles are evergreen, and can remain on the tree for up to 9 years, but usually fall after 2 to 4 years. The sheath is 3 ⁄ 16 ″ to ⅜ ″ long, eroding to 3 ⁄ 32 ″ to ⅛ ″ long as the needles age, but not falling off before the needles. The needle pairs are spreading but are not forked. Needles are borne in bundles of 2 with a sheath at the base. The white dots are pores surrounded by 2 glaucous cells, and are evident on all surfaces. In cross section they are triangular in shape and have 2 fibrovascular bundles. They are slightly or strongly twisted, stiff, and sharp-pointed. They are usually 1 ½ ″ to 2 ½″ long and 1 ⁄ 16 ″ wide, but may be up to 3 ½ ″ long. The needle-like leaves are bluish-green, grayish-green, or yellowish-green, with evenly distributed white dots. They are usually thinly or sometimes thickly covered with white resin. The buds are egg-shaped to cone-shaped, ¼ ″ to ½ ″ long, sharp-pointed, and covered with overlapping reddish-brown scales. They become grayish-brown and rough in the second year. The twigs are slender, greenish-brown to orange-brown, not glaucous, grooved, ridged, and hairless in the first year. ![]() The tree’s age can be determined by counting the number of whorls from the bottom up. They horizontal and whorled, each whorl representing one year of growth. Bark on the upper stem and branches is thin, bright orange-red, and smooth, and peels off in papery flakes and strips. On mature trees the bark on the lower part of the tree is thick, grayish- to reddish-brown, deeply furrowed into irregular, longitudinal, loose, irregularly rectangular, scaly plates, with the brownish-red inner bark revealed between. The bark on young trees is orangish-brown and flaky. The trunk is sometimes straight, but is often crooked due to growing conditions, pests, and diseases. Older trees have a broad, done-shaped or flattened crown. Young trees are pyramidal in shape with a cone-shaped crown. It is the most widespread pine in the world. In Minnesota mature trees are usually 30 ′ to 50 ′ tall, though in favorable conditions it can reach over 90 ′ in height. Scotch pine is an evergreen, coniferous tree rising on a single trunk from horizontal roots and, usually, a taproot.
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