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Pinus rigida, the pitch pine, [2] [3] is a small-to-medium-sized pine. It is native to eastern North America , primarily from central Maine south to Georgia and as far west as Kentucky. It is found in environments which other species would find unsuitable for growth, such as acidic, sandy, and low-nutrient soils.
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This template calculates the per annum compound growth rate given two pairs of years and populations (or other time periods and units) using: P A G R = [ ( P 2 P 1 ) 1 t 2 − t 1 − 1 ] × 100 % {\displaystyle PAGR=\left[\left({\frac {P_{2}}{P_{1}}}\right)^{\frac {1}{t_{2}-t_{1}}}-1\right]\times 100\%}
Where: Y is the yield (volume, height, DBH, etc.) at times 1 and 2 and T 1 represents the year starting the growth period, and T 2 is the end year. Example: Say that the growth period is from age 5 to age 10, and the yield (height of the tree), is 14 feet at the beginning of the period and 34 feet at the end.
The mean annual increment (MAI) or mean annual growth refers to the average growth per year a tree or stand of trees has exhibited/experienced up to a specified age. For example, a 20-year-old tree that has a stem volume of 0.2 m 3 has an MAI of 0.01 m 3 /year.
This variable indicates the rate of biomass increase per unit leaf area, with typical values ranging from 5-15 g.m −2.day −1 for herbaceous species and 1-5 g.m −2.day −1 for woody seedlings. Although the ULR is not equal to the rate of photosynthesis per unit leaf area, both values are often well correlated. [7] [8]
Unusually for a pine, the cones normally point forward along the branch, sometimes curling around it. That is an easy way to tell it apart from the similar lodgepole pine in more western areas of North America. The cones on many mature trees are serotinous. They open when exposed to intense heat, greater than or equal to 50 °C (122 °F). [16]
Pinus jeffreyi occurs from southwest Oregon south through much of California (mainly on the eastern side of the Sierra Nevada), to northern Baja California in Mexico. It is a high-altitude species; in the north of its range, it grows widely at 1,500 to 2,100 m (4,900 to 6,900 ft) altitude, and at 1,800 to 2,900 m (5,900 to 9,500 ft) in the south of its range.