Tuesday, March 10, 2009

Giants

From small seeds. Ned Barnard alerts us to the fact that giant sequoia (Sequoiadendron giganteum) cones like the inch and a half long specimen above may mature for 20 years on the tree before dying and releasing their seeds. The cones can produce over 200 seeds. In natural conditions, on the eastern slopes of the Sierras, the trees don’t produce large cone crops until they are 200 years old. Other than the bristlecone pines, giant sequoias are some of the oldest life forms. Hardcore AMNH fans may recall the big slab of crosscut they have on display. For those of us on this coast, we should note that the coast redwood (Sequoia sempervirens) is a different tree. The coast redwoods, as their name suggests, grow on the western edge of northern California, where they depend on thick rolling fogs and the rain shadow effect. I’ve had the good fortune to walk among them in Muir Woods National Monument. I’m not aware of any around here: the climate conditions are not right. We do have a relative, however, the dawn redwood (Metasequoia glyptostroboides), which was known only as a fossil until 1941, when live ones were discovered in China. In addition to botanical garden samples, there is one on Houston St. & 2nd Avenue at the Liz Christie Garden. Deciduous conifers, they rather look like bald cypresses (Taxodium distichum). How to tell them apart? Look for the Parks Department nameplate....

2 comments:

Xris (Flatbush Gardener) said...

Parks nameplates are not always correctly assigned!

Both Taxodium, Bald Cypress and Metasequoia, Dawn Redwood are included in BBG's Woody Landscape Plant Identification class. They're both in the Cupressaceae, the Cyrpress family.

The ways I distinguish them is that Dawn Redwood has more reddish bark. And if you see knees growing in or near the water, it's a Bald Cypress.

I'm sure there are more technical characteristics to distinguish them, but I can't recall them off-hand.

Matthew said...

Too true about those nameplates! Let's get some needles for comparison later this year.