Dwarf Forests   Don Bertolette
  Nov 11, 2004 07:43 PST 

I've been wearing my ecological restoration hat a lot lately. From a
restoration point of view, it's often helpful to look at reference
conditions (conceptually similar to "natural or historical ranges of
variability). The tree measuring ENTS is doing is definitely squaring away
the precision and accuracy part of the equation, but by measuring only the
tallest trees you can find (I understand the calling!), isn't ENTS only
halfway there? You're getting the top range of variability (let's say of
the population of old trees), but in terms of restoration of these same
remnant populations, it would be valuable to have the lower range of old
tree sizes...

RE: Questions for Jess and Will   Robert Leverett
  Nov 11, 2004 09:36 PST 


    Good question. You point to a bias in our treatment of tree growth.
I usually think in terms of how well a tree species can do for a set of
conditions. It is hard for me to think in the other direction, although
there are exceptions. For instance, the dwarf pitch pines that growth on
a couple of summits in the Mass Taconics and I think several mountain
tops in the Catskills reflect a waist to head-high forest that
perpetuates itself forest generation after forest generation. It seems
natural to acknowledge what the species is doing in these austere
environments. So I readily accept that to fully appreciate and
understand Pinus rigida, we need to study its capacity to survive across
the range of conditions in which we find it.

    Extending this thinking to the other species seems to be the logical
move. But do we seek the best a species does when growing in stunted or
dwarfed form - or do we look for the most extreme case of stunting? Or

    Looks like we need to add a good yardstick or even foot ruler to our
measuring paraphenalia.

Re: Questions for Jess and Will   Don Bertolette
  Nov 11, 2004 18:57 PST 


I too am interested in the performance of a species across a continuum of
conditions...ponderosa pines on the Kaibab Plateau (includes North Kaibab
District of USFS and the Grand Canyon) have had a continued presence for
more than 8,000 years
( http://jfsp.nifc.gov/conferenceproc/Ma-11Bertoletteetal.pdf ) on soils that
are in lay terms, shallow and not very rich in nutrients. So few
exceptionally tall or large diameter trees are to be found (tough area for
the champion tree hunter!). However, as a forest restorationist, the range
of variation that this gene set exhibits after a multi-millenial run is very
interesting data. It may be instructive to know that 300 year old ponderosa
pines naturally ranged from 21"dbh to 57"dbh, and heights ranged from 67' to
Particularly to other land management agencies that don't have the extensive
array of ponderosa pines as relatively undisturbed as ours.

RE: Questions for Jess and Will   Edward Frank
  Nov 11, 2004 19:56 PST 

Bob, Don, Colby, other ENTS

All of you have seen these stunted trees or pictures of them. Many do not
reach "breast height" or if they do they are relatively far up the trunk of
the tree. If you were to try and document these stunted trees in a similar
shorthand format for larger trees at what height would you measure the
circumference? I would suggest a point just above the root flair (ABF?)
with the actual height from the ground specified. Any comments or

I must confess I am fascinated by these stunted forms and would like to see
and participate in documenting the trees in such a forest.

At the other extreme are the Giant Sequoias and the like that are so large
root flare may extend upward of thirty feet, and if on a slope on side of a
cbh may be on the ground at the upper end and high of the ground on the
downslope side. But all in all you can still measure something like a cbh
for them. Bob Van Pelt has done a very nice job of mapping the footprint
of many of these trees and has shown virtual slices of the trunks of these
trees at varying heights.

Ed Frank

Re: Questions for Jess and Will   Don Bertolette
  Nov 12, 2004 18:27 PST 

I too am fascinated by the "bonsai" segment of old-growth...when they are of
human dimension, it's possible and I'd think desirable to "map" it like BVP
(good practice in humility, in the face of what BVP accomplishes with the
superlative end of the spectrum!!!).
Your comments about redwoods recall my forestry classes at Humboldt State
U., with labs up the street in the coastal redwoods...simple tasks became
epic...dbh measurements required art, and a red rubber ball...we'd impale the
hook of a D-tape into a red rubber ball, and after carefully loosening (much
like getting fly fishing line out there) up some tape, we'd swing the ball
around the base (we'd be on a 80-100% slope, on topside of tree base) that
would often be 350 inches in circumference (not uncommon to measure 10-12
foot dbh redwoods less than a mile from classrooms). Had to make a good
catch, as the back side was often 15 to 25 foot above the base on the
downhill side...all this with ferns growing over your head, and 5-7 months a
year, muddy. Caulked boots were standard wear (like a golf shoe bottom, but
many more spikes and much sharper). Ah, those were the days!
Dwarf Forest Study Plan   Edward Frank
  Nov 12, 2004 18:50 PST 

Bob, Don, and other ENTS,

I am sure we have enough of a brain trust here on the ENTS discussion List
to work out a good strategy for looking at these dwarf stands of trees.
Bob Leverett showed some slides of the dwarf pitch pines on some
Massachusetts mountains during the forest summit a few weeks ago. These
trees were spaced relatively close together, but did not look like they
formed a continuous canopy. I would suggest the following strategy to
characterize a site such as this:

I would do a transect line across an area inhabited by these trees. The
specific direction of the transect and initial starting point could be
selected prior to visiting the site based upon topo maps of the area. This
would provide a degree of randomness to the location of the line. The
initial starting point and ending point of the transect could be located
via GPS and marked with a small cairn in case the site merited another
visit at a future time. Every tree that had any part of its canopy extend
within a set distance, say ten feet of the transect line would be measured.
Measured would be the distance along the transect line from the starting
point, the distance from the transect line to the left or right to the
tree, the circumference of the tree, the height of the tree, and the canopy
spread of the tree.

I would make a measuring pole the length of the set distance to be measured
from the transect line. A short right angled bend could be placed at one
end of the pole. This would make it easy to determine if a tree extended
within the study width and enable the measurer to accurately place the tree
at a correct distance along the transect line. Each tree right or left
would be numbered sequentially. The circumference would be measured at the
same height for each tree. That height would be determined by field
observations made at the site and noted in the field notes. The
measurement could be done using any tape, even a short cloth sewing tape
available for a dollar. The most efficient way to measure height if they
averaged less than 15 feet would be to use a rigid measuring pole. The
crown spread would be measured as per Will's measuring document.
Additional information could also be noted such as height to the first
living branch, live crown ration, etc. Of course species would be noted if
more than one were present.

The location information and crown spread could be used to create a map of
the trees (crown spread represented as a circle) and the area of the canopy
versus open space could be calculated. For trees that have only part of
their canopy within the measuring distance there is an equation that can be
used in a spreadsheet to calculate the area of the arc segments within and
outside of the boundaries. That is one example of a calculation that could
be made. Additional notes could be made based upon things you found in the
field of interest. Whether a tree is mature or just a sapling should be
noted. Clumps of other vegetation within the transect area would be worth
noting and identifying...

I would photograph each tree measured with a digital camera - a negligible
cost -. Since each tree would be given a unique number. A number placard
could be used to show the tree's number in the photo. I am thinking
something like the flippable numbers used to mark prices in stores.
Illustrative characteristics could be photographed, with a scale, for use
in any reports or presentations.

A second group of trees that should also be measured in the process is any
tree within the grove or site that warrant special attention, the tallest
tree, the shortest tree, the one with the greatest diameter, or other
special characteristics. They should also be located with respect to the
transect, maybe by using the laser range finder. The results would be
tabulated on a separate list.

The ages of the trees should be determined. Perhaps a couple could be
cored. If there was a dead tree in the grove a slab could be cut for later
examination with a small handsaw. Evidence of disturbance events should be
noted. Boundaries for the dwarf tree area should be noted on the topo map.
GPS could be used to confirm placement of these boundaries.

Ed Frank

Re: Dwarf Forest Study Plan   Don Bertolette
  Nov 12, 2004 19:46 PST 

My preferences for canopy closure are:
1)aerial photography (digital orthophotoquads cover most of the united
states at nearly one meter resolution...
2)if on ground, a GRS densitometer, as found at
http://www.grsgis.com/densitometer/index.htm, with an excellent write-up on
Re: Densiometer   Edward Frank
  Nov 12, 2004 20:00 PST 


Thanks for the suggestion. I looked at the website you listed. I have
skimmed the paper by Stumpf listed and downloaded it for a more detailed
examionation. In my first impression, I am wondering about the
applicablility of the (vertical) densiometer in a canopy that may only be 5
feet off the ground and very stragglely. Also, I don't have a densiometer,
while I do have a tape measure and compass. But the idea warrents further

With regard to aerial photos, I am thinking the scale we are dealing with may be a problem. The canopy spread for a particular tree may only be a few feet across and would barely be distinguishable on most air photos. At this point I am just tossing out ideas and thinking about the problem. The purpose of the post was to fish for ideas and to pique someone elses interest in the problem. I would like to try it myself, but probably won't have time till next summer.

I know you mentioned the resolution of one meter for the orthophotoquads. But to make reasonable measurements you need to be measuring something significantly larger than the minimum resolution of the photograph.


Re: Densiometer   Don Bertolette
  Nov 12, 2004 20:20 PST 

You have done well with things easily at hand, a "McGuyver" of the transect

Re densitometer, I hadn't been envisioning 5 foot tree heights (haven't been
to Bob's pigmy forest), it would work equally well for a tall man, using
densitometer inverted (ie, "looking down" instead of up...
The thing I like about the densitometer, is that it's appropriate
technology...abs plastic tubing, levels, wires, plexiglass. Lightweight,
and it's accuracy dependent on operator field skills...plus, its list of
applications is limited only by the user's imagination.

I still like the aerial view...doesn't cost much to rent a plane, take
aerial photos with a digital camera. Easiest way to determine boundaries by
crown level vegetation, even with DOQQs and small crowns...when crowns get large enough to perceive, new boundary...

Re: Dwarf Forest Study Plan   David Orwig
  Nov 16, 2004 09:35 PST 
Just a quick reply related to sampling dwarf forests. Depending on what
you actually want to characterize, a series of fixed area plots has worked
for us in past on dwarf communities in the southern Taconics and in the
Shawangunks in New York (see references below). Briefly, you establish
fixed area plots and measure soils, overstory vegetation (dbh, height, ages
etc.) within them, and understory veg, in a series of smaller nested
subplots. thanks 


Abrams, M.D. and D.A. Orwig. 1995. Community and radial growth dynamics
of a 320 year old pitch pine rock outcrop community in southeastern New
York. Oecologia. 101:353-360.

Motzkin, G., D.A. Orwig, and D.R. Foster. 2002. History and dynamics of a
ridgetop pitch pine community: Mount Everett, Massachusetts. Harvard
Forest Paper Number 25.

Motzkin, G., D.A. Orwig, and D.R. Foster. 2002. Vegetation and
disturbance history of a rare dwarf pitch pine community on Mount Everett,
Massachusetts. J. of Biogeography 29: 1455-1467.

Dwarf Forest Comments   Edward Frank
  Nov 18, 2004 21:23 PST 


I have had a couple of stray thoughts I wanted to add to the dwarf forest mix.

1) I am curious to what degree the stunted Jack Pines talked about by Bob
L. are of that form because of the climate directly, and what part of that
has been imprinted on their genetic code by thousands of years of natural
selection from living in that harsh climate. Seeds from cones collected
from one of these dwarf forests could be collected and then planted in an
area known to grow large pine trees. Records could be kept over the course
of several years of the growth of these particular seedlings. The
long-term study could be done as a side piece to an existing or planned
long term study, could be grown on a university setting study plot, or
perhaps grown by a commercial grower. If the trees indeed have a large
genetic contribution to their diminutive form, and stayed small over time,
they could even have a place in the landscaping business.

2) When I was doing cave research in The Bahamas, one of the karst features
I was looking at for an overview were areas containing dense concentrations
of pits. The individual pits were located on a fairly flat surfaces, were
3-10 feet across and dropped vertically 15-30 feet. Several people had
been working on them and had previously deduced their origin. The problem
was that there had never been any good pictures taken that gave a proper
perspective of the pits and their surroundings. I had the idea of taking a
tall step ladder to one of these areas with us. Then shooting from atop
the ladder we could get a better angle to show the pits, pit complexes, and
the surrounding flat areas. There was a line up of people in at the field
session waiting their turn to take pictures from atop the stepladder. If
the dwarf forest areas were not too far up the trail from a road access, a
good step ladder could do wonders for taking pictures of the small trees
and the surrounding terrain.

Ed Frank
Re: Dwarf Forest Study Plan   Jeffry Littleton
  Nov 23, 2004 05:30 PST 


In regards to sampling dwarf forests, it might be best to survey a series
of random plots within the forest. Based on aerial photography and an
initial site visit, the study area can be stratified. Then, using a GIS a
grid system can be placed over the area and plots chosen at random. The
belt transect method could also be used and would probably be less
time-consuming and easier to implement. However, random plots might yield
more accurate information. Having said this, the sampling method really
depends on the information one would like to obtain.

Although I have not sampled the pitch pine/scrub oak forests on the summit
of Mt. Everett, while conducting research on the remainder of the forest I
have often found myself atop the mountain in this dwarf forest. There can
be a great deal of variability depending upon slope aspect,
micro-topography, substrate, and disturbance history (and therefore,
degree of succession). I have sampled some of these dwarf forests on other
sites on the mountain using a systematic sampling scheme to delineate
forest communities and to characterize species composition and age
structure within each community, including basal cover, relative
frequencies, and height. This method was developed to characterize the
eastern portion of the mountain, including a smaller pitch pine community
to the east of the summit. This sampling scheme was adequate to obtain the
desired information. However, to fully understand and characterize these
dwarf communities random plots would be better.

Harvard Forest conducted research on the pitch pine/scrub oak forest on
the summit of Mt. Everett. They utilized a random plot sampling scheme
that seemed to work well.

Motzin, G., D.A. Orwig, and D.R. Foster. 2002. History and dynamics of a
ridgetop pitch pine community, Mt. Everett, MA. Harvard University,
Petersham, MA. Harvard Forest Paper No. 25.

They aslo published a paper in the Journal of Biogeography in 2002. Sorry,
can't seem to find the paper at the moment for the whole citation.

Re: Dwarf Forest Study Plan   Edward Frank
  Nov 23, 2004 18:49 PST 


I have gotten a post concerning the plan from Dave Orwig and from you
concerning the idea of a belt transect versus a plot format. I have never
designed a forest survey and have been looking for input. Realizing that
these numbers are for comparison purposes what would be the benefits and
weaknesses of various plot plans. For example: a) a single plot 100 feet
by 100 feet, and b) four random plots 50 feet by 50 feet, c) a "belt"
transect 20 feet wide by 500 feet. All of them cover the same area.

a) A single plot site that was larger would provide much more detail for
that portion of the forest and allow better internal comparisons to be made
between tree within the plot.

b) Four random plots (or selected plots even) would provide details from
four separate areas of the site. There is a much greater chance to
document variations in the site.

c) A transect would show variation in the forest along a single line and
ideally it would provide information on the transition between one variant
of the forest and another. More than one transect section could be done.
I also believe it would be easier to implement than the other options.

What thoughts do you have on why one design variation would be better than
the others? What are the benefits and weaknesses of each of the sampling
design options? I would be interested in hearing more details of the
methods you used in your research and why you choose that methodology over
other methods.

Ed Frank