Wednesday, May 28, 2008

Thyme and spontaneous fires.

A cushion of this was in glorious purple bloom by the west end of central trail. I IDd it as Coridothymus capitatus, a kind of thyme. It's not the same species as the common spiny aromatic scrub but same family I think. It will be interesting to compare the flowers when the latter blooms. Pic zoomed ~ 2x nat size.

Today's range: 16.2-25.1 degrees C. At about 6.30 p.m. it was down to 22.5 degrees.
Humidity 44%, wind NW 6.1 kt, skies clear.

Observations today gave much support to husband's theory about the spontaneous nature of the fires. No new fires broke out today but we went to check out yesterday's fires. The ground cover of the Pistaccio orchard had burned patchily- at least three different patches, each roughly under a set of trees with unburned area between.

You have to look carefully to discern shadows from burnt patches

Fallen leaves and other debris under the trees would build up, decompose and in the constant light of the sun heat further till the dried thorns and grasses above ignited. Ground around the Pistaccios within the eucalyptus grove was unburned. This was usually in the shadow of the first and tallest line of eucalyptus and would receive little sun. A few yards farther north patchy fires had broken out under some of the eucalyptus.

The south west part of gazelle field burned yesterday. Feeling the ground it was still quite warm on the surface, 24 hours after the fire had gone out. Digging a few inches down the ground was quite hot! Could a fire ignited deliberately at the surface have such an effect? Much of the soil in this section is quite rich and alluvial and there's something like a peat build up effect, deeper layers generating and holding heat and the sun beating down on it all day. This makes it all the more amazing that plants can regenerate from this, they're clearly adapted to the temperatures.

Why no fires last year? (the fire recovery pic. was at an old Lag BeOmer bonfire site) That's an easy one. The heavy rains of May 12th dampened the earth and prevented them but that meant TWO years of build up of organic debris and the result being a much greater incidence of fires this year compared with earlier years. It all makes sense now. Then as this year we'd assumed they were caused by man but thinking about that build up it would certainly account for the abrupt increase over earlier fires- we are looking at it all in a whole different way!

Birds today: Garden, much calling of house sparrows, white spectacled bulbuls and sunbirds. More distant small calls of something psittacine, the ring necked parakeets probably. Jackdaws. Laughing doves and Feral pigeons around as usual, former, ground and lines, latter, building tops and sky. The Feral pigeons leave street foraging to the doves most of the time, they must wait till it's quieter to forage, they seem a little more timid or perhaps smarter!

Near look-out corner, much cooing of collared doves and turtle doves, A number of bee-eaters over the orchard and eucalyptus grove, hard to tell how many, a dozen to 20 plus, all would return to perch in trees intermittently (probably to remove the stings from their catch and eat them, so they'd be out of sight and we wouldn't see the whole group at once) Greenfinches singing as usual toward sunset. Chaffinch like song heard both in the eucalyptus grove and at look-out corner though I'm actually wondering if it's a creative greenfinch variation as there seem to be greenfinch like sounds in the song too.

Syrian woodpeckers calling and drumming (drumming heard yesterday too, forgot to mention), Blackbird high pitched 'tzeeet' alarm calls and some song. Graceful warblers vocal. Plenty Eurasian jays and hooded crows about, foraging. Masked shrike heard in pine grove, then Pistaccio orchard, possibly the same individual. Stone curlew heard in the outlying fields. We didn't manage to find any gazelle today though I scanned the hillside to the north a few times as well as north gazelle field and east field. Grazing on the hillside not damaged.

More recovery after 3-4 weeks old fire in the north valley. Not sure what this plant is yet. One of many.

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