|
Above: Ponderosa Pines grow to more than 50 metres in height and from .9 E2.4 metres in diameter. Stands cover approximately 11 million hectares of land in the United States. The large plates of orange-brown bark distinguish mature Ponderosa from other pines; needles grow in clusters of three. |
Ponderosa Pine
Pinus ponderosa
Forestry
Ponderosa Pine thrives from Canada to Mexico and from the Pacific Coast eastward to the Black Hills of South Dakota, an area that stretches over more than 35 percent of the area of the United States. The typical site for this abundant species is on semi-arid plateaus and slopes, often surrounded by juniper and sage, with its rate of growth dependent on altitude, soil, temperature and rainfall.
Mature Ponderosa Pines are easily identified by their distinctive orange-brown bark, arranged in large plates. Trees average 30 to 49 metres in height, with some exceeding 60 metres; diameter ranges from .6 to 2.4 metres. The dark, yellow-green needles are 127 mm to 254 mm long and grow in clusters of three. The cones, similar in colour to the bark, are 76 - 152 mm long and 51 - 102 mm in diameter. Seeds are 9-9.5 mm long with a 20 - 25 mm wing.
Most trees grow, mature and survive for about 125 years before they are lost to natural causes such as rot, insect damage, fires or wind throw. Occasionally, a lone specimen will survive for nearly 200 years. Ponderosa for timber production are selectively harvested to remove the most mature trees, leaving younger ones to thrive and re-seed.
Western White Pines
| Ponderosa | Sugar | Lodgepole | Idaho White | |
| Height Range | 38 - 60 m | 48 - 76 m | 14 -26 m | 45 - 54 m |
| Diameter Range | 0.9 -2.4 m | 1.2 - 3.5 m | 0.3- 0.5 m | 0.6 E1.2 m |
| Specific Gravity1 | 0.40 | 0.33 | 0.41 | 0.36 |
| Mean Weight2 | 458 kg | 408 kg | 474 kg | 440 kg |
1 Specific gravity at 12 % moisture content. Range for
softwoods is 0.31 - 0.55.
2 Mean weight per cubic metre at 12 % moisture content.
Softwood range is
376 - 670 kg; 425 kg is average for White pines.
