With branches dropping and trees falling, stormy winter weather roared back with a vengeance this month, reawakening drought-conditioned Californians to an almost forgotten sensation – really wet.
We’re waterlogged, and now we’re worried. What could make an 80-foot redwood topple over? Is there any warning before a big branch falls? How do we cope with the muck without causing harm to our homes and gardens?
Arborist Kurt Stegen knows what happens when big storms hit, like the ones that have battered Northern California this month.
“I saw a couple of conifers go over (Jan. 10), both cypress trees,” said the Loomis tree expert. “Redwoods have had a lot of root loss during the drought. If individually placed, they can fall over.”
All it takes is a strong gust of wind and soil saturation for some massive evergreen trees to be uprooted, he noted.
About 5.4 inches of rain fell on Sacramento just between Jan. 7 and 10. Before the ground had a chance to dry out, more storms arrived this week.
Conifers – redwood, pine, fir, spruce, yew, juniper, cypress, etc. – in particular are at risk, Stegen said. These evergreen trees retain their foliage year-round and can become top-heavy. During storms, those needles become saturated with water, holding extra weight on a tree’s branches. That foliage also catches the wind like a huge sail.
“Once the ground is saturated, it doesn’t take much to push them over,” he said. “And the soil in some areas is almost liquefied.”
When the wind is blowing, you can see the ground actually move. That’s scary.
Arborist Kurt Stegen
Redwoods and other evergreens grown close together, similar to a forest grove, helps stabilize the trees, Stegen said. “Their roots become intertwined and they help hold each other up. But when they’re just standing by themselves, they’re susceptible.”
As for deciduous trees, these January storms are knocking down birches, elms and other specimens weakened by years of drought.
“The problem we see right now are those trees that are almost dead – or had already died in 2014, 2015 or 2016 – they’re falling down,” said Kuldeep Singh, a longtime community forester with the Sacramento Tree Foundation.
The problem often can be traced to the roots, particularly for “lawn trees” – solitary shade trees surrounded by turf, Singh said. Shallow watering, as what happens with lawn sprinklers, leads to shallow roots and lack of support.
“Really, it all starts when the tree was planted,” he added. “Hopefully, you helped your tree put down good strong roots by proper irrigation.”
The drought shrunk the root ball of many big trees, Stegen said. “People are shocked when they see the roots of some these fallen giants. The roots look so small for such big trees, and they are. It’s a reminder people should water their trees deeply to develop deep roots.”
Strong winds knocked down dead or dying branches out of trees of all kinds, Stegan noted. Those branches were drought casualties.
Healthy deciduous trees are less likely to uproot in winter than their evergreen counterparts, because without their leaves, the weight is drastically reduced, Singh noted.
During a break in the rain, it’s a good opportunity to go outside and take a look at your trees,” Stegen advised.
“We’ll see cracks in the soil around the base of the tree; that means something’s happening (with the roots below),” he said. “Or the tree … starts leaning more. You may see the ground raise up around the base of the tree. When the wind is blowing, you can see the ground actually move. That’s scary.”
If your soil is waterlogged, you want to stay off it.
Master gardener Timm Johnson
Those signs may indicate imminent danger, he said. “Get some yellow tape out and rope off the area around the tree. You don’t want anyone under it.”
Other dangers to look for, Stegen said, are broken limbs caught in other branches, crotch separation where the trunks meet on multitrunk trees and heavy branches without sufficient support.
If any of those signs are present, call an arborist immediately, he said, to stabilize the tree, trim it back and reduce the size and weight of the tree.
“After several years, the tree will re-root and support itself,” Stegen added.
Homeowners have to cope with trees on their property, Singh noted. Median, street and park trees are the responsibility of city and county urban forestry divisions.
“If you spot a tree in trouble (on public land), call the proper agency so they can take care of it,” he said. “The tree foundation can always advise people, too. If you anticipate something (such as falling branches), take photos.”
What if the problem is at ground level, as in too much water with nowhere to go?
“If your soil is waterlogged, you want to stay off it,” said Sacramento County master gardener Timm Johnson, who suggests walking on board planks instead of wet soil.
Healthy soil contains tiny air pockets that allow plant roots to “breathe,” and compaction squeezes out that necessary air and plants die.
During storms, notice where water accumulates in your landscape, he said. “You don’t want it to pool next to your foundation. Also, most plants don’t like standing in water. You need to redirect that water away from your house – but not just into your neighbor’s yard.”
In low spots, that storm water may percolate down into your own landscape. That’s the theory behind “rain gardens” with berms to create temporary holding basins for rainwater to deeply irrigate nearby trees, shrubs or perennials.
Don’t forget potted plants during storms, Johnson said. They can fill up with rain, drowning the plants inside. Bonsai and succulents are at greatest risk.
“When it rains like this, I tip my pots sideways,” he said. “I lay them on their sides so the water can drain out. I put the succulents under the eaves so they don’t get swamped. They’re a lot happier that way.”