Ponderosa pine (Pinus ponderosa) and eastern white pine (Pinus strobus) are two pine tree species that exhibit different levels of shade tolerance. While ponderosa pine is considered shade intolerant, eastern white pine is more shade tolerant and can grow in partially shaded areas.
What is the Shade Tolerance of Ponderosa Pine?
Ponderosa pine is a shade intolerant species, meaning it requires full sun to thrive. When growing under a light overstory that casts 50% shade, its growth rate slows by half compared to full sun conditions. Ponderosa pine typically grows in even-aged patches due to its intolerance of shade.
How Tall and Wide Can Ponderosa Pine Grow?
Ponderosa pine can grow up to 100 feet tall and 50 feet wide at maturity. Its growth rate is significantly reduced in shaded conditions, growing at half the rate of associated species like Douglas-fir, sugar pine, white fir, and incense cedar.
What Soil and Moisture Conditions Does Ponderosa Pine Prefer?
Ponderosa pine grows on a wide variety of soils, including those of igneous, metamorphic, and sedimentary parent materials. It prefers soils that are medium in texture and release moisture readily. Summer soil moisture is a key factor in determining whether ponderosa pine will grow in a particular area, as it grows better in areas with average rainfall and can tolerate drought once established.
How Does Ponderosa Pine Respond to Environmental Factors?
Ponderosa pine is vulnerable to overcrowding and responds well to thinning between the ages of 70 to 100. It is also relatively fire-resistant due to its thick bark and open crown.
What is the Shade Tolerance of Eastern White Pine?
Eastern white pine is more shade tolerant than ponderosa pine. It can grow in areas with partial shade, although its growth rate is still affected by the reduced light levels.
How Tall and Wide Can Eastern White Pine Grow?
Eastern white pine can grow up to 100 feet tall and 50 feet wide or more at maturity. It often reaches 50 feet wide or more, making it a good choice for shade trees.
What Soil and Moisture Conditions Does Eastern White Pine Prefer?
Eastern white pine grows well in a variety of soils, including those with low fertility. It prefers well-drained soils and can tolerate some drought. However, it requires adequate moisture, especially when young, and can tolerate some drought once established.
How Does Eastern White Pine Respond to Environmental Factors?
Eastern white pine is often used as a shade tree and can provide habitat for various bird species. It is not as fire-resistant as ponderosa pine due to its thinner bark.
Ecological Implications of Planting Ponderosa Pine and Eastern White Pine in Shaded Areas
Planting ponderosa pine and eastern white pine in shaded areas can have different ecological implications. Ponderosa pine, being shade intolerant, may not thrive in densely shaded areas and may require more maintenance to ensure its survival. Eastern white pine, being more shade tolerant, can grow well in partial shade and can provide shade for other plants and animals. Both species can play important roles in forest ecosystems, but their specific growth habits and shade tolerance levels should be considered when selecting trees for planting.
Reference:
1. https://funfactsabouttrees430792891.wordpress.com/2021/03/04/pines-as-shade-trees/
2. https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_1/pinus/ponderosa.htm
3. https://ucanr.edu/sites/forestry/Ecology/Identification/Ponderosa_Pine_Pinus_ponderosa/