Out here in Douglas County, we have a discussion going about ponderosa
pine cone crop - or the lack thereof. In Castlewood Canyon State Park, the west
side has only a handful of trees with a handful of cones; Karen Metz says,
"portions of the East Side of the park do have pine cones - and Red-breasted
Nuthatches. I also heard Red Crossbills there this past summer."
Today we walked the park's East Canyon trail. It traverses habitat similar
to the paved trails on the east side, but because you clamber over rock & rough
places, it seems wilder and more inviting. Before the trail reached the highway
we saw at least 30 juncos, smaller numbers of Pygmy & White-breasted
nuthatches, Mountain Chickadees, White-crowned Sparrows, & heard a few
Townsend's solitaires & flickers. The juncos congregated at some wet seeps to
drink and especially to bathe. We walked maybe a mile on the east side after
the trail goes under the highway bridge, and when we came back we saw no birds
at all. Zero. [The park will close the trail Nov. 3 for about six months ("to
protect nesting raptors").]
Deerfield, a subdivision about 3 miles east of The Franktown traffic light,
seems to have lots of cones. This summer Karen saw 2-3 pairs of Red Crossbills
that fostered two broods -- she saw 7 fledglings one morning in early October.
She also has flocks of Pine Siskins, a few Cassin's finches, and some
Red-breasted Nuthatches.
We have missed cone crops for the last 3 or 4 years on the Black Forest
Christmas Bird Count (El Paso/Douglas) and seen few on our spring & fall trips
to Genesee Mtn. Park (Jeffco).
The cone crop generated a local discussion, and Jeff Thompson, Resource
Stewardship Program Coordinator for the state Parks & Wildlife, shared this from
http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/pinus/ponderosa.htm
"Seed Production and Dissemination- No regular periodicity has been
observed in the seed production of ponderosa pine over its entire range. In
California, west of the Sierra Nevada, medium seed crops are borne on an
average of every 2 to 3 years. The average interval between heavy cone crops is
8 years. Good cone crops are produced every 3 years in the Black Hills (7),
every 3 to 4 years in the Southwest (55), and every 4 to 5 years in the Pacific
Northwest (3). Observations over 23 years in Montana show ponderosa pine to be
a poor seeder west, and a fair seeder east, of the Continental Divide, with
only one good crop. The species bears cones as early as 7 years and continues
to produce good seeds to at least 350 years. Seeds from trees aged 60 to 160,
however, are more viable than those of younger or older trees. In California,
trees more than 64 cm (25 in) in d.b.h. were the best producers. In central
Idaho, mature and overmature trees growing at an elevation of 1680 m (5,500 ft)
produced lower quality seeds than similar trees at 1220 m (4,000 ft), and open
grown trees produced heavier crops of larger cones than stand grown trees (13)."
Hugh Kingery
Franktown, CO
[Posted partly due to a quiet Cobirds the last week, but also to generate a
discussion]
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