San Dimas Experimental Forest

Bigcone Douglas-Fir (Pseudotsuga macrocarpa) in the San Gabriel Mountain National Monument — Part one

I have always wanted to visit the San Dimas Experimental Forest and as part of a mapping and monitoring project for bigcone Douglas-fir, I finally had the opportunity. The “forest” descriptor in the area’s title is a bit misleading, as the majority of the vegetation is chaparral–but there are trees and it was our mission to find them (or at least what remains). Six major fires have been documented here since 1914, with the most recent occurring about 10 years ago. These fire events, along with climate change, are rapidly reshaping the remaining stands of trees. What follows is a photographic journey into the front range foothills of the eastern San Gabriel Mountains.

Cucamonga Wilderness from the San Dimas Experimental Forest.

Cucamonga Wilderness from the San Dimas Experimental Forest.

Regional Map

Looking past a low elevation, south-facing stand of bigcone Douglas-fir toward the Inland Empire.

Looking past a low elevation, south-facing stand of bigcone Douglas-fir toward the Inland Empire.

The long and narrow road through the San Dimas Experimental Forest.

The long and narrow road through the San Dimas Experimental Forest.

Low elevation mortality surpassed 50% in stands of bigcone Douglas-fir.

Low elevation mortality surpassed 50% in stands of bigcone Douglas-fir.

I presumed the extensive mortality was caused by drought stress and bark beetles -- but I'll be able to look deeper into this in October.

I presume the extensive mortality is being caused by drought stress and bark beetles — but I’ll be able to look further into this in October.


Fern Canyon Research Natural Area – San Dimas Experimental Forest

From the RNA Report:

Low-Elevation Ponderosa Pine: Brown’s Flat, a shallow 80-acre (32-ha) bowl created by an ancient land slump, contains the lowest elevation stand of Pinus ponderosa in S. California (about 3900 ft, 1189 m). This relictual stand of 81 individuals is well-isolated from other ponderosa pine stands in the San Gabriel Mountains and strongly affected by air pollution. There is almost no recent reproduction.

We counted 27 individuals in September 2015.

Two images, 45 years apart, show the decline of the lowest-elevation stand of ponderosa pine in the Angeles National Forest.

Two images, 45 years apart, show the decline of the lowest-elevation stand of ponderosa pine in the Angeles National Forest.

From the RNA Report:

Bigcone Douglas-fir: The stands of bigcone Douglas-fir at Fern Canyon have burned recently (1975). Poor reproduction suggests that the fire had a negative effect on seedling and sapling establishment. However, many of the larger trees, although scarred, survived the fire. The local stands should provide interesting comparisons with other stands in Millard Canyon and Falls Canyon RNAs, which have not been affected by fire for many years.

Stand-replacing fire mortality. While canyon live oak is returning, only bigcone Douglas-fir snags remain.

Stand-replacing fire mortality. While canyon live oak is returning, only bigcone Douglas-fir snags remain – this fire occurred approximately 10 years ago.

6 thoughts on “San Dimas Experimental Forest

  1. Pingback: Bigcone Douglas-fir - Plant Explorations

    • Aaron- Great question, but difficult to answer. First, I’m assuming your are asking about the Brown’s Flat ponderosa pines…I think the best approach is to get in touch with the Angeles National Forest botanist and encourage initiating a project that maps the remaining trees. We will then, at least, have a baseline moving forward.

      • Thank you. I just moved to San Dimas and just learned of the Expoerimental Forest. Currently I attempting to grow Live Oak from accorns i gathered from Walnut Creek. I hope we can do the same with Ponderosa and the Bigcone if they ever produce again. Is air polition and intense fires the main reason for their sterilization?

  2. I am exploring the planting of the Big Cone Spruce/Douglas Fir macrocarpa on our property east of Clovis CA at about 3800Ft elevation. As you might know the Ponderosa Pine has been almost wiped out by the bark beetle. My friend that is the forester for Southern Ca. Edison has suggested using this tree for replanting, mixing it with pine and cedar. From the description of soil and other requirements the macrocarpa might grow perfectly, sheltered among the live and black oaks. The question is where is a source for purchase. I thank you in advance for your ideas and assistance.

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