Scott Fiore has a question about desert trees

[Scott Fiore]

Hi, I live in a Sunset zone 12 (Intermediate Desert) and am looking to plant some fast growing shade trees. Does anyone have any suggestions? Thanks!

-Scott Fiore

[Scott Fiore]

Hi, I live in a Sunset zone 12 (Intermediate Desert) and am looking to plant some fast growing flowering vines. I am thinking about Bougainvillea but wanted to also do something different. Does anyone have any suggestions? Thanks!

-Scott Fiore

[David Hare-Scott]

Have a look at genus Eucalyptus. There are over 500 species of all sizes suited to all kinds of condtions including very hot and fairly dry. Some are very fast growing. If you select the right kind for the climate and soil they can be very durable. Depending on where you are there may or may not be much choice available for sale. I seem to recall there are some specialist vendors in the USA.

David

[paghat]

But they are banned in some areas because they present an unusual fire hazard, each tree a gigantic match waiting to ignite.

Try to get a copy of Mary Rose Duffield's PLANTS FOR DRY CLIMATES, which tells a lot about trees that can thrive in desert climates. Some need regular watering but don't mind the weather extremes. Others are low water maintenance but those tend to be slow growers.

Look for information on acacia trees. At least a dozen species are in nursery production for desert gardening, with cultivars in many interesting forms. The genus is to desert gardening what oaks and beaches are to temperate gardening, with endless variety available.

Scarcer but in production are Ceridium species & hybrids, with various forms & varieties though some have the look of multi-branching shrubs except thirtyt feet tall, and some have the most unusual (and beautiful) pitted bark. They can be thorny but there's a thornless cultivar.

You should also track down your nearest native plants society -- I can't imagine a region that doesn't have either a small independent organization or a volunteer service with a government agency doing planting and salvage work. Through such organizations you can almost always get legal access to native species that aren't in nursery production.

-paghat the ratgirl

[paghat]

Sonoma County is one of the places where eucalyptus have a proven record of fire hazard, and one of the first places to experiment on mass removal and control regrowth of eucalpyts (in Annendel State Park), as they're as difficult to eradicate as himalyan blackberry is for those of us in the Northwest. It is a VERY EXPENSIVE multi-year project to remove these trees from any given area, and the Sonoma experiments figured out how to do it with a four year project and lots of yucky herbicides without which they'd never be gotten rid of ever. The emergency need is to get rid of them in national parks where they are injurious even before they catch fire, and from areas where they grow near homes.

"The non-native eucalyptus trees are aggressive growers and are particularly dangerous in a fire. Once ablaze, the gummy trees tend to explode, spewing out blazing material that can land miles away, sparking new fires." [UC Berkley News]

Projects exist in Sonoma, Medicino, Marin and other California counties to get rid of them but only where they pose the greatest threat. If you can live in California and know nothing about this, perhaps you need to broaden your attentiveness to local events.

When you can smell the eucalpytus, that means its highly volatile oils are clinging to the ground in the atmosphere. "Eucalyptus oil catches fire very easily, and bush fires can travel quickly through the oil-rich air of the tree crowns," a wikipedia artical notes.

In 1991 eycalpytus were the primary fuel threat that resulted in the loss of 3,400 homes killing 25 people in the Oakland Hills. They are rightly chary of letting the eucalyptus ever again become the dominant tree in the area. As "fire-prone exotics that push out native species" they are no loss.

The LIVING tree is a fire hazard, and in fact eucalyptus is adapted to regrow from the ground after it has completely burned. No need to dry out at all, which is why in Whittier, California, 3,000 healthy eucalyptus trees were removed as fire hazards. They are invasive trees as well, and the 6,000 eucalptus trees removed from hills surrounding the University of California, Berkeley, as part of their fire prevention project, were in the main not planted there intentionally.

25,000 eucalpytus were removed from the Claremont Canyon where they had not only already proven to be major fire hazards, but being adapted to regrow after fires much mroe rapidly than can native plants, they were a menace to the whole ecosystem generally. In Australia eucalyptus adaptation to fire has insured the survival of forests by growing back rapidly and reproducing best after a burn. But in western US environments they out-compete native shrubs and trees and contribute to natural habitat loss while increasing future fire hazard. A mixed conifer forest will not burn as rapidly as eucalyptus, and foar this reason in some firebreaks the tree removed first if not exclusively will be the eucalypts. As invasives they're hard to get rid of because even cut flush to the ground & routed out with a wood shredder, they sprout back up like mad.

It's ubiquity and invasiveness is alone reason not to plant the buggers on purpose, but for fire hazard reason they are banned in many areas in California, and rightly so.

-paghat the ratgirl

[symplastless]

Scott

I am ignorant about where your zone is (lack of knowledge). A specimen of a tree biology workshop was a Gamble Oak. It thrives in the Desert near Salt Lake City, Utah. You don't see a gamble oak you see gamble oaks. They thrive in groups. I think they said they were a shorter tree. They are ring porous and form tyloses in most vessels other than the current growth increment. In other words, the sapwood, in a cross section reveals that the tree has conducting and nonconducting sapwood. Sapwood, older than one year, have their vessels plugged with tyloses. A balloon type structure. The back cover on 100 TREE MYTHS by Dr. Shigo has a dissection picture.

Where is zone 12?

[David Hare-Scott]

That's interesting. I never thought of banning them, there being a few zillion here. You wouldn't grow them near your house as they do burn well and some drop branches. But growing any big tree near your house is not smart in my view, there are so many ways that they can do damage. The giant match image seems a little alarmist but perhaps eucalypts are less well behaved compared to cool temperate trees.

I like acacias too. I didn't recomend them as most are more in the shrub/ small tree category. The larger ones that I know are adapted to wetter and cooler conditions. I am not saying there is no such thing as an acacia dryland shade tree (there is how many to choose from 1000?) but I thought eucalypts was a better bet.

How big are the ones in nursery production that you refer to?

David

[Scott Fiore]

Thanks so much for all of the great recommendations and advice!