Sequoia sempervirens seed collection, Auckland, NZ.

ByTodd Haskell Services

Do you seek a contract tree climber to collect botanical material from Sequoia sempervirens or other tree species for research or forestry? We can help you.

The most common reasons an arborist has for climbing trees outside of training usually consists of diagnosis, maintenance, & felling, however other reasons include, retrieving items such as drones,  & obtaining seeds for propagation.

A recent job detailed here was for the purpose of seed cone collection from a coastal redwood tree (Sequoia sempervirens).

Coastal redwood trees famously grow taller than any other species & are long-lived growing well over 1000 years, with the oldest known example ~2200 years old!

Their native range was originally a narrow strip of N.W. California coast & a tiny proportion of S.W. Oregon (Olson,  D.  F.,  Roy, D.  F.,  Walters, D.  F.,  1990).

I was contacted by Rob Webster who had identified a specific tree laden with cones in a stand he manages. Rob explained he’d observed the tree had insect borer & was seemingly the only tree in the stand that was producing. Rob informed me the tree cones were about to release seed & now was the time to collect as many of the cones as feasible & requested my services with the collection. Rob provided knowledge, research articles & inspiration for this blog, & deserves full credit.

Sequoia sempervirens seed was apparently first imported from California 1860s (Gaman, T., 2012). Many of NZ’s coastal districts having similar climatic conditions as California were found to produce favorable growing conditions for the tree leading to its rapid growth here.

The timber has unique characteristics making it a desirable &  economically important forestry species. In NZ trees are planted and are planned to produce clear-sawn logs within 25-40 years, with consistency a requirement to sustain the industry (Gaman, T., 2012).

With planting an economically attractive investment, & demand rising, most planting stock is being sourced from tissue culture, however, the higher propagation time from tissue culture makes seed collection for propagation an attractive option.

Unlike conifers such as Pinus radiata which release seeds from their cones after cones have fallen, coastal redwood trees release their small inconspicuous seeds from cones whilst cones remain attached. Thus requiring the aerial collection of cones for seed harvest.

Sequoia sequoia are monecious meaning male & female cones are produced on the same tree. Female cones become receptive & pollen is shed from male cones between late Autumn and Early Spring. The seed develops and female cones start opening the following year in Early Autumn & shed until the first month of Winter (Olson et al., 1990).

Coastal redwood trees may not produce seeds every year, & within a stand of coastal redwoods, only some trees may produce & not others.

Seed viability is variable, with favorable seed-bearing age reached after 20 years, becoming optimal between 60-100 years, after which being observed to be less viable (Roy, D.F., 1966).

The cones born on the terminal end of branchlets require getting out to the ends of branches for collection. As cones are small & quite tough to remove by pulling off by hand, it was planned to cut ends of alternate branches.

My plan to climb was to set a line from the ground to the highest branch I could reach and then use an alternate lanyard technique to advance to the top where I reset my main climbing rope which I would then use as support to limb walk out to ends of branches & make pruning cuts with a top handled pruning chainsaw, & handsaw.

This proved effective & was able to collect the desired amount within the specified timeframe, without injury or damage to property.

If you are interested in contract climbing services or other any other tree services, get in touch for a free quote. Call or TXT Todd: 021340320

Photo showing a very small sample of seed cones collected after being dried out & releasing seed
Photo showing a very small sample of seed cones collected after being dried out & releasing seed (the seed is the very small round objects).
REFERENCES

Gaman, T. (2012). California’s coast redwood in New Zealand. General Technical Report (GTR). In: Standiford, Richard B.; Weller, Theodore J.; Piirto, Douglas D.; Stuart, John D., tech. coords. Proceedings of coast redwood forests in a changing California: A symposium for scientists and managers. Gen. Tech. Rep. PSW-GTR-238. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp. 611-615

Olson,  D.  F., Roy, D.F., Walters, G.A., (1990): Sequoia sempervirens (D.  Don)  Endl.  Redwood.  In: Silvics of  North  America:  1.  Conifers.  Burns,  R.M.,  Honkala, B.H.,  (Technical  Coordinators).  Agriculture Handbook. U.S. Department of Agriculture. Forest Service, Washington, pp. 541–551.

Roy, D.F., (1966) Silvical Characteristics of Redwood (Sequoia sempervirens [D. Don] Endl.) Berkely, Calif., Pacific SW. Forest & Range Exp. Sta 20 pp., illus (U.S. Forest Serv. Res. Paper PSW-28)

When is best to prune trees in Auckland?

ByTodd Haskell arborist tips & advice

In temperate Auckland, where our local business operates, lesser seasonal variation of our weather may reduce need to follow strict pruning guidelines required elsewhere. There are several instances however where time of year should be considered.

For deciduous trees, any significant pruning which is timed for late Autumn, or Winter has several major advantages over pruning over other times of the year. Pruning Autumn/Winter maximises deciduous tree’s ability to photosynthesize & store energy over the active growing seasons, energy required for respiration, production of response growth, & to defend against disease. Another advantage of Autumn/Winter deciduous pruning, absence of leaves makes visually assessing tree branches in the canopy easier. Yet another advantage, absence of nesting birds.

For some species of evergreen trees, reduction pruning should be avoided around the peak of summer, when the suns rays may burn cambium of newly exposed branches.

Some tree species susceptible to disease should only be pruned at certain times of year to avoid being infected when the contagion is present. Stone-fruit trees, for example should be pruned in Summer & not in Winter to avoid silverleaf fungal infection. Citrus trees should be pruned during winter & not in the warmer months to avoid citrus borer insects. Prune apple & pear trees & other trees susceptible to fire blight in late Winter.

Deadwood removal can be done at any time of year as no live tissue need be removed.

The best time for pruning trees is when they’re newly planted, when structural defects can be corrected to allow tree to direct future energy into healthy growth.