Arguments For and Against
Mount Pisgah Arboretum
Should the Arboretum Plant Trees from Around the World?
I Strongly Favor this Policy!
by Theodore W. Palmer, January 18, 2012
Arguments against International Planting:
1 Some species might escape and become invasive.
This has not been a problem in other arboreta regionally or world-wide. From the very beginning we set up policies to ensure that this would not happen.
I am particularly sympathetic to the concern that such planting will endanger the Howard Buford Recreation Area. Along with Howard and many other people, I have seen the size of this contiguous, compact area (now including the Wildish Land) and its connectivity by river corridors to other wild areas of Oregon as the best chance to preserve native habitat within an area which will surely become more urbanized. If I felt any significant concern that our planting plans would endanger this function I would not support planting. I drew our 1996 boundaries, so that all drainage is internal to the Coast Fork. Although I think it is almost impossible that we would ever plant an invasive species, if we did so by mistake, it should not impact any other part of HBRA. Obviously the Coast Fork drains our whole lease area. However the danger of invasive vegetation problems upstream are enormously larger than any we might pose.
2 Some local organizations with whom we wish to co-operate may be opposed.
This may be true and is unfortunate, but any organization must make its own policy decisions. MPA did so 38 years ago. Experience elsewhere shows that any opposition is likely to decline rather quickly.
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3 This will interfere with the presentation of our local flora.
The plan for introducing non-native species has always been to do so in restricted areas. Many years into the future we can be sure that well over 80% of the Arboretum site will have managed but un-invaded local flora as it does now. In addition one of the greatest advantages of our site is that it will remain surrounded on three sides by a compact area of several thousand acres managed to preserve local flora
4 This will be difficult and expensive.
It is unquestionably true that the implementation of the plan we have had from the beginning is difficult. That is one (but not the only) reason why it has never been undertaken seriously. However, when we have achieved the proper planning, our plan should entail very little additional expense. (See F below.)
Arguments in favor of International planting:
A This was the purpose for which our organization was founded.
The first sentence of our Statement of Purpose and our Articles of Incorporation has remained almost unchanged from its adoption in late 1972. The second sentence was added much later to satisfy some founding members who were concerned that the original purpose was being forgotten. Here are these two sentences:
The purpose of this organization shall be to establish, maintain and perpetuate an arboretum of highest quality for the public benefit; to acquire and grow plant specimens from our own country as well as from other countries around the world; to encourage conservation, research and awareness of ecology; to assist education on all levels in the natural sciences and arts; and to provide facilities for the public enjoyment and the use of its gardens. The organization was founded upon the idea of a garden featuring plants from around the world growing together to symbolize international friendship.
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Lane County’s application to the State of Oregon to manage the area later named the Howard Buford Recreation Area gave as the first in a list of uses of the site development of “an International Arboretum”. The state required these plans. MPA is the only one of the many uses listed that has actually come close to fruition.
B The majority of the support for the Arboretum (particularly the Endowment) has been given by those who have understood that this is our purpose.
Of course I do not know the names or ideas of everyone who has contributed money, leadership and volunteer work to the Arboretum. However I do happen to know the names and ideas of all those who have been major financial contributors, and of all those who have ever served on our Board of Directors. The vast majority have always considered (and, if living still consider) international planting to be the core goal of the organization. Until comparatively recently there has never been any question that this was a fundamental part of our mission.
C This will be a great gift to Lane County and all of Oregon.
Trees provided the main support for Lane County for most of its history, but the area is singularly poorly supplied with displays of many of the most interesting trees. The University of Oregon Campus and our urban forest are rich, but not organized primarily for appreciation and study. Oregon has only two arboreta of any note. Hoyt Arboretum in Portland founded in 1922 (and specifically designed after the Arnold Arboretum, where I grew up) has over 1,100 species of woody plants growing on 187 acres. Peavy Arboretum in Corvallis has about 173 species of woody plants growing on 40 acres, The only first class arboretum within 500 miles is Strybing Arboretum in Golden Gate Park in San Francisco. The only other nationally known arboretum in our general area is the University of Washington’s Washington Park Arboretum. It was founded in 1934 (earlier roots in 1895, and reorganized in 1983) and designed by the Olmsted Brothers also after the Arnold Arboretum. There are 4,451 recognized species growing on 230 acres.
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A well planted collection (even on a modest acreage) of the most interesting tree species from around the world is spectacular and will attract many more visitors. I am confident that it will be one of the chief tourist attractions of central Lane County.
D This will make it much easier to get grants and other forms of support.
At the present time we have perhaps the best developed of many local areas displaying local flora. However there is nothing truly unique about our site except its remarkable ecological diversity and its intensive use for education. International planting of trees will provide something distinctive. There are many organizations and people who will want to support it. I have served on granting committees. They generally want to support things that are not already available locally. One of the greatest advantages of MPA’s site, is that it is surrounded by about 4,000 acres which is being managed to restore and maintain native vegetation. No addition is needed.
E This is the highest use of our outstanding site.
Since I was a small child I have visited as many arboreta and botanical gardens as I could. I believe our site is outstanding on a national (and to the extent I can judge) international basis. It would be a shame, and a dereliction of responsibility, not to develop this site to its highest potential.
F From the beginning this Arboretum has had a unique and valuable plan for doing this.
Most arboreta are organized on one of two plans: F1 Botanical Sequence, or F2 Geography. From its very beginning our organization wished to emphasize ecology over either of these principles. Thus we developed in some detail F3 Ecological Planting. The idea is simple. Trees and shrubs from around the world and from any botanical order or clad will be planted and grouped in the ecological conditions that favor them. To a certain extent all planted collections use this idea by necessity, since a wet loving tree cannot thrive in a dry environment. We wish to make a virtue and a teaching aid out of necessity.
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At the present time the taxonomic relationships of all living things are being radically reorganized by the use of genetic information so the F1 plan is not really feasible at present. Our founding idea was to emphasize that woody plants from around the world could grow in harmony. Thus plan F2 is undesirable. We have always believed that our F3 plan was in line with the most important educational mission of an arboretum in the 20th and 21st Centuries.
Operationally, this means identifying 8 to 10 outstanding focused sites within the Arboretum in terms of hydrology, sunlight, soil type, etc. For each ecological location the majority would be preserved permanently with its native vegetation. Another few acres (say less than 2 to begin with and up to 6 or 8 eventually) would be gradually cleared of most (but not all) native woody vegetation. As this is done, carefully chosen non-native woody plants would be planted and nurtured. This probably requires a full-time botanical, horticultural, landscape design and planting expert on staff. Thus it will only begin to happen when we have attracted significantly more funds. However, with a Board fully committed to our original plan I have no doubt that that it will be possible.
G This is the only way to fully achieve our educational mission.
From its beginning our arboretum has always wanted to emphasize ecology. Native trees are not enough to fully illustrate ecological principles.
A related idea is that people tend to remember what is unusual or particularly beautiful. There are hundreds of species of fascinating and beautiful trees that we can introduce.
H Although Oregon is known throughout the world as a place where trees grow, it has a very limited flora of woody plants.
Our present 209 acre site is about as ecologically diverse as is possible in the southern Willamette Valley. Yet our plant list gives only 23 species of native trees and 8 species of native woody vines and shrubs. At present there are 15 species of non-native trees and 1 species of non-native woody shrub (Scots Broom, Cystis scoparius). More than half these non-native trees were introduced on purpose and a few are unwanted invasive species e.g. English hawthorn (Crategus monongyna, by far the most common) and English holly (Ilex aquifolium). In many areas of our country and the world a single un-diverse acre of woods might have as many as 40 woody species.
From its beginning our arboretum has always wanted to emphasize ecology. Native trees are not enough to fully illustrate ecological principles.
A related idea is that people tend to remember what is unusual or particularly beautiful. There are hundreds of species of fascinating and beautiful trees that we can introduce.
Theodore W. Palmer 