Home from holiday, straight to the garden - January, and the frogs are floundering on spawn jelly bags, singing the songs of spring in the sunshine. Next day the woods had to be visited. Unfortunately the weather had changed. The roads were flooding again. The paths were mud. It was mild so the badgers had been rooting for food and re-locating their latrines. Birds were lively, great tits sawing out their spring songs. There is a good sprinkling of shiny dark green holly seedlings. The lighter, green leaves of celandine and pennywort gleamed in the rain from their fat beds of rotting leaves. A raven flew silently through the oak trees. Following its path backwards we saw a large nest near the top of a tall oak. Long-dead trees lying in a gully covered in moss were gleaming with an almost fluorescent intensity. My holiday felt like Bede's sparrow in his Ecclesiastical History, "from winter going into winter" - what could it understand of the king's feasting hall?

I'd been to Lanzarote, a volcanic island whose last eruption was in 1824. There, rain is only a dampness. Some parts are a wilderness of desolate, black viciously sharp rocks. The Timanfaya National Park covers an area which was a fertile plain until the eruptions of 1730-36, now it is a desolation of volcanic cones and craters, but like all deserts it has a strange attractiveness. The visitors' centre has a cooking spit using geothermal heat. An attendant spoons you some lava debris to hold. You can't, it's too hot. Dry scrub smoulders and flares, but the most bravura trick is to pour a bucket of water into a pipe stuck in the ground. Two seconds later it re-appears as steam with the explosion of a rocket going into space. Vineyards use volcanic rock as a circular protection for each vine against the wind and as a means of catching the dew. Their lava mulch looks like cinders. Already mosses and lichens which can withstand the heat are colonising the rocks. Did Pembrokeshire look like this millions of years ago?