by Nick
Grzenia
The genus
Eucalyptus currently has 600 different species that can be found in many
countries around the world. Each country
the tree is found in has its own use for the quick growing species. Uses of the species range from firewood to
building material, to hardwood products seen in cabinetry. Nearly all of the species of eucalyptus
originates from Australia, with some species found in the United States on the
west coast in central and southern California.
This tree made its
way to the western US by seed brought by immigrants that headed west during the
gold rush. A boom occurred from 1905-1912 where the species was readily planted
but interest was lost years later with the US being involved in wars and a
depression. The 1950’s and 60’s showed a
renewed interest and the tree was planted and used in the production of
fiberboard. In the 70’s, eucalyptus was
widely used as an alternative energy source through biomass fuel. It wasn’t until the 1980’s the tree was grown
and harvested on a large scale for the production of biomass and pulp/paper.
Eucalyptus,
because it has such a small range in the US, it has a few climatic and
landscape needs for adequate growth and survival. The tree does best in areas with warm
temperatures and temperate winters (15-100 degrees F), moderate rainfall, dry
atmosphere, and plenty of sunlight which is readily available in central and
southern Cal. The tree is also somewhat drought resistant but not very tolerant
of frost damage. The genus also prefers
soils that are loamy, deep, and well drained, being that it does not grow well
in standing water. Generally in the
areas of Cal. it is found on poor sites, while agriculture is the land use on
the rich sites.
The auteology of
eucalyptus includes seeds that are readily produced after 20-40 years with only
a few in each capsule being fertile. The
seeds also respond well to fire or disturbance. The foliage is of a green/grayish color that
is leathery and contains oils which give the tree a distinct odor. The bark
does vary by species, with some species regularly shedding bark, giving the
tree a smooth, white appearance at times.
The roots of this tree are of any typical tree species, with a tap root
extending 6 ft into the ground with fibrous roots extending 100 ft from the main
stem that can cause damage.
Currently some species of eucalyptus are
considered invasive by some groups in Cal.
Because the species has the ability to naturalize, it is taking over
some sites in Cal. which has slowed the planting of certain species. The two species of concern are blue gum (Eucalyptus
globules), and red gum (Eucalyptus
camaldulensis). Currently none of these
species are listed on a state or federal level as invasive.
With eucalyptus vastly
becoming a popular species not only for pulp/paper production but for biomass/biofuels
harvesting it is important to know how to manage the species. With many different types of silvicultural
practices out there the most popular is clearfell and burn. Advantages of this type of practice are as
follows: 1) creates a uniform seedbed of
heat-sterilized mineral soil. 2) when followed by slash-burn, it creates a more productive
regrowth forest, due to enhanced nutrition of the seedbed and higher light
intensities. 3) it is the most cost-effective method of harvesting and
regenerating eucalyptus. Some
disadvantages are: 1) generally negative attitude from general public. 2) creation
of an extreme visual impact, reducing landscape values. 3) Potential nutrient and organic matter loss
from high intensity slash-burns.
There are other silvicultural
practices being used on eucalyptus species each bringing a unique set of
advantages and disadvantages to that species and stand. Other practices include: clearfell with
mechanical disturbance, seed-tree with burn, stripfell and patchfell and
shelterwood.
Works
Cited
·
Paine, Timothy, Donald Dahlsten, Jocelyn Millar,
Mark Hoddle, and Lawrence Hanks. "California
Agriculture." California Agriculture Online. N.p., 11/2000.
Web. 29 Apr 2012.
<http://californiaagriculture.usanr.org>.
·
Hickey, J.E., M.G. Neyland, and O.D. Bassett.
"Rationale and design for the Warra silvicultural
systems trial in wet Eucalyptus obliqua forests in Tasmania." 13.2
(2001): 155-181. Print.
·
Crous, P.W. "Mycosphaerella spp. and their
anamorphs associated with leaf spot diseases of
Eucalyptus.." (1998): 1-170. Print.
1 comment:
Very interesting topic and I agree completely. I am also a fan of eucalyptus trees, however, their invasive tendencies are a major concern. The historical information and genus description although interesting, are not critical here. The advantages of slash and burn logging were covered well but I feel like the disadvantages are extensive enough to build a very strong argument. A comparison of of the different silvicultural methods should have been made also. Given the invasive tendencies of eucalyptus, you could have possibly mentioned some alternative species and why eucalyptus may be a better choice. I realize there is only so much you can say in 500 words and I think the topic is excellent and the argumentis not far behind. Especially given the length, I think you provided a significant amount of useful information so that most everyone could understand the issue at hand.
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