Using tree tubes to establish native California oaks from acorns

We have been talking about various applications and uses of tree tubes.  One broad area where tree tubes have proven their mettle is in ecological restoration, more specifically the re-establishment of critical native species into environments that are no longer "native."  A great example of this is the use of tree tubes for California native oaks.

Tree tubes are being used coast to coast to help re-establish native trees whose numbers have dwindled due to disease (particularly in the case of the might American chestnut in the east) or to a combination of grazing, fire suppression, competition from exotic grasses & weeds, deer browse, rodent damage, and disease (in the case of California's native oaks).

As you can tell from that laundry list of threats, successful establishment of California oaks is not easy in 2012.  The mature oaks that line the golden hills of California got their start in a completely different world, before livestock grazing, before the spread of European annual grasses that have largely replaced less competitive native perennial grasses and forbes, and when fire - both lightening caused and as part of the vegetation management strategies of California's indigenous people - helped suppress competition giving oaks time and space to grow large enough to shade out competition.

Tree tubes to the rescue!  It is a truism that a) the more important it is that a particular tree get successfully established*, and b) the greater the threats to that tree's survival, c) the more more it makes sense to use tree tubes.

* Then again, in the same way that police officers should never draw their gun unless they intend to use it, people should never plant trees unless they intend for them to survive and thrive. 

All of this makes tree tubes the perfect tool for helping restore and re-establish California's beautiful native oaks.  And one of the best ways to plant California oaks is be direct seeding acorns and protecting them with tree tubes.

Blue oak acorns ready for planting

(Click to enlarge)

Planting acorns, chestnuts, black walnuts, and hickory nuts directly in the soil and protecting them with tree tubes is a practice that is really catching on.

In this case this blue oak (Quercus douglasii) acorns are being planted on former ranch land that is being converted to an oak preserve in the Sierra foothills near Springville, CA.

The acorns were gathered from local blue oak trees, to ensure that they are well suited to the climate and soil.  They were then soaked in a pail of water for 24 hours, and any "floaters" were discarded (floating after that period of time is a sure sign that weevils or other insects have burrowed into the acorn and have eaten all of the nutmeat that is needed to produce a new seedling).

Then two acorns are being planted in each planting hole, about 1 inch deep and loosely covered with soil.  Each set of 2 acorns is then being protected with 6 foot Tree Tubes for protection from deer, but more importantly from the cattle that will be grazing on this property for the next few years as part of a lease agreement.

The tree tubes will:

Protect the acorns and seedlings from rodents (except burrowing ground squirrels; other measures are being taken to protect from them)

Protect the seedlings from getting browsed or trampled by cattle (steel t-posts are being used for stakes, with a second, shorter stake being used on the opposite side to prevent cattle from rubbing against the tube and pivoting it around the stake.

Shield the seedlings from deer browse.

Greatly reduce moisture stress in an area that goes months without rain and where temp's often top 105 degrees.

Facilitate effective weed control, so annual grasses do not take the limited soil nutrients and moisture these oaks will need.

 

 

Tree tubes are proving to be an absolute must for the successful establishment of native California oaks.  Are tree tubes "natural?"  No, but then neither is the environment into which we are planting those native oaks - too many cattle, too much grass seed, and too little fire.