Monday, January 19, 2009

Coast! Live! Oak!

My first tree of 2009 is the Coast Live Oak (Quercus agrifolia). Of all the trees in Golden Gate Park, this is the only species that is native there....and there's a whole lot of them. It's fun to learn a tree you see a lot, because everytime you walk by one you can say "coast live oak" (say it out loud and give it a wave).

How do you know if you're looking at a Coast Live Oak? Their height is pretty variable, from 25 to 40 feet, so height could throw you off. To be sure, check out their characteristic leaves.

Coast Live Oaks have round to oval shaped, brittle leaves, generally with several spine-tipped teeth. Look for tufts of hairs on the bottom of the leaves.

Monday, January 12, 2009

bats in the ggp!

Holy cow it was nice outside today.

Walking home from work today, not far out of the building, between the tennis courts and the AIDS memorial grove about a dozen bats zoomed around my head. So rad.

What kind of bats were they?

Turns out there are 23 bat species native to California, 14 in the Bay Area. It was dark, they were fast and I don't know a thing about bats, so I won't even attempt to ID them.

In doing some google sleuthing I found out that the USGS has been doing bat surveys in the Bay Area, and has a great website that has all kinds of bat vocalizations. Check it out.

USGS bat inventories in the San Francisco Bay Area

Friday, January 9, 2009

First rock of 2009-Serpentinite

South side of the Mint (Safeway parking lot)

In addition to wanting to learn more about trees this year, I also want to learn more about rocks. Luckily, I can use kind of a similar approach to both subjects. Neither trees nor rocks go anywhere very fast, so I can use our vast collection of field guides to look stuff up post-wandering, and if I can't figure out what something is, I can go back and take another look (and maybe bring a camera).

Alright. First rock of the year is serpentinite, a hulking mass of which holds up the mighty Mint at Market and Dolores. It's a metamorphic rock found on the sea floor at tectonic boundaries. Serpentinite often contains veins, some of which may be filled with a form of asbestos called chrysotile.

Pay attention to serpentinite – if you see fibrous veins, don’t touch the rock.

I didn't see any fibrous veins in this rock, but I also didn't get that close. Not surprisingly, they have a big old fence around the Mint. And very stern looking guys with guns. They may even have guard crows. I kid you not, as I was walking around the building trying to find a place to take a picture a crow flew over me and dropped a rock square on the top of my head.

Little bit of trivia? It's the California state rock.

More trivia? This hill used to be 90 feet high, but they shaved off the top 40 feet to build the Mint. Our very own mountaintop removal project.