More info for the terms:
adventitious,
cover,
forest,
formation,
litter,
mast,
root collar,
seed,
stratification,
treeSexual reproduction: Seed production begins when the tree is about 20
years old, although open-grown trees may begin producing by 15 years.
Poor acorn crops occur in 3- to 4-year intervals. Dissemination is by
animals, primarily squirrels, mice, blue jays, and woodpeckers [
19].
Over a 4-week period, blue jays transported and cached 54 percent of the
available pin oak acorn crop from a stand on the campus of Virginia
Polytechnic Institute and State University in Blacksburg. The high
percentage may be skewed, however, because of the high number of
consumers per tree on a campus compared to a forest. The mean transport
distance between seed trees and caches was 0.7 mile (1.1 km), with a
range of 0.06 to 1.2 miles (0.1-1.9 km). Pin oak acorns fall within the
preferred size range [0.4 to 0.7 inches (1.1-1.7 cm) in diameter] of
blue jays [
6].
Pin oak acorns require a 30- to 40-day cold stratification period at 32
to 41 degrees Fahrenheit (0-5 deg C). Viability is high. Acorns
submerged in cold water for as long as 6 months were not damaged. A
thick waxy coating on the pericap restricts water absorption [
19].
Seedling establishment is often high after a good acorn crop year. In a
study in southeast Missouri, there were an average of 3,500 seedlings
per acre (8,650/ha) following a high mast yield [
19]. Pin oaks are most
likely to establish if the litter layer is 0.5 to 2 inches (1.3-5.1 cm)
deep. Pin oak germination and early establishment can occur under a
dense canopy, but seedlings will die after 2 to 3 years unless they are
released. In a study of pin oak regeneration in southern Illinois, 1-
to 2-year-old seedlings were more abundant under a closed canopy than in
an open stand where the ground cover was dense. Seedlings over 5 years
of age, however, were more abundant in the open stands [
13].
Two-year-old pin oak seedlings subjected to three shade treatments
increased their shoot/root ratio by 26 percent with increasing shade, a
reaction typical of intolerant species [
18].
In a study in southern Illinois, pin oak reproduction was most abundant
in mixed hard-hardwood communities composed of oaks (Quercus spp.) and
hickories (Carya spp.); low in mixed soft-hardwood communities composed
of silver maple (Acer saccharinum), green ash (Fraxinus pennsylvania),
sweetgum, hackberry (Celtis occidentalis), and American sycamore
(Platanus occidentalis); low in eastern cottonwood (Populus
deltoides)-black willow (Salix nigra) communities; low in old fields;
and rare in newly formed land (i.e., exposed sand bars) [
14].
Pin oak seedlings are classified as intermediate in tolerance to shallow
flooding during the growing season [
12,
19]. After 60 days of completely
saturated soils, pin oak seedlings averaging 8.2 inches (20.8 cm) in
height had no shoot mortality, sparse adventitious root formation, and
some mortality of secondary roots. Seedlings under saturated conditions
grew significantly (p less than 0.01) taller than the control seedlings [
12]. In
another study, seedlings subjected to shallow flooding (leaves and tops
exposed) during the growing season survived 84 days, but root growth
ceased, growth was poor, and recovery was slow. Seedlings survive only
10 to 20 days of complete inundation during the growing season. Pin oak
seedlings suffer no adverse effect from dormant season flooding [
19].
Vegetative reproduction: Pin oak seedlings and young trees sprout
vigorously from the root collar if top-killed [
19].
