Underburning, Tiny Seeds, and Massive Trees

Redwood Mountain UnderburningA VISIT TO THE GIANT SEQUOIAS 

A recent trip to southern California provided an excuse for my first visit to Sequoia and Kings Canyon National Parks.  We arrived on a cool summer evening, with a beautiful sunset made all the more vibrant by the large amount of smoke in the air.  Although pollution from the San Joaquin valley is indeed an issue in the southern Sierra Nevada, in this case the source of the smoky air was more local: there was a large prescribed underburn going on a few miles away.  The next day were drove on a windy road toward the center of the park and were rewarded with a spectacular view of Redwood Mountain with plumes of smoke arising from the forest.  With a friendly “no problem” from the park service ranger, we drove down a dusty road through magnificent fire-scorched sequoia trees to the perimeter of the burn.

Sequoia Tree PhotoThere we found a crew with radios and drip torches monitoring the burn and helping it along by lighting accumulations of fuel.  Although it was summer, it was cool and relatively moist at this elevation – about 6,500’ – and the fire behavior seemed benign.  I learned from a crew member that they planned to underburn 600+ acres in this operation, with most of the ignitions accomplished by helicopter.   

Prescribed underburningHome to one of the largest giant sequoia groves in the world, Redwood Mountain is said to be the birthplace of prescribed fire in the United States.  The grove was last burned in 1977, so by the 10-15 year fire cycle in sequoias, it was overdue.  Prescribed fire is used here to reduce hazardous fuels, so that when wildfire does occur, it does not kill the giant trees.  It’s also needed to provide an ash-rich mineral seedbed which giant sequoia trees require for regeneration.   While the species mix is a bit different, these forests face many of the same issues that we do in SW Oregon – too many trees, too dense, too much fuel, and increased risk of high intensity fire.

The scale of prescribed burning in Sequoia and Kings Canyon NPs is truly impressive.  On several hikes we walked through recently burned areas, with lots of fire-scorched trees and here and there patches of young trees including sequoias, which had regenerated after the fires.   Sequoia coneMost of the stands appeared to underburn, leaving the larger overstory trees alive, but there were small patches of overstory mortality here and there.  According the park website, they planned 3,600 acres of prescribed underburning in 2012 alone.  

The only negative, and it did detract a little, was the smoky air.  Good planning made it possible to avoid breathing too much smoke, but there were few if any magnificent Sierra vistas to be had during our brief visit.

Off the tourist track

Looking at General Sherman or one of the other iconic trees in the park is like a little like visiting the Mona Lisa: there is a large crowd, cameras click, parents admonish small children, and tour busses rumble in the distance.   But even with all the bustle, it’s easy to enjoy some quiet:  just get off the paved trail.  As soon as the tread is dirt and duff, 98% of the people stay behind.  (And I don’t mean to sound snobbish about the crowds- I think it’s great that people are enjoying the parks and being inspired by the huge trees).  

Signs of UnderburningThe mixed conifer forests of the area are impressive even without the sequoias.  Mature white fir, incense cedar, and ponderosa pine and common and some of the sugar pine would be considered giants by southern Oregon standards.  But they are all completely dwarfed by the sequoias, which routinely exceed 20 feet in diameter and 200 feet in height.  

Still standing

The spatial patterns of the sequoias are interesting. They
often occur in clumps or small groups, with gaps between the groups.  This is just what you’d expect with a pattern of frequent, relatively low intensity fire.  Most had fire-scorched bark, and a few were burned completely through, and still standing.  Wow.  

Healthy Canopy-Sequoia

It’s not just the sequoias, though.  I enjoyed the granite outcrops, the dogwood in bloom, and the intensely green meadows interspersed between groves of trees, among many other attractions.

It’s a special place, and I’ll be back.

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