Rights-of- W ay, from, page 1 
quarters of the funding conies from the 
Empire State Electrical Energy Research 
Corporation (ESEERCO). This funding 
consortium manages research and 
development money contributed by New 
York State’s utility companies, and a 
portion of the money is allocated for 
environmental research. 
Untold millions of seeds are produced by 
trees bordering rights-of-way, but 
relatively few germinate and survive to 
emerge above the surrounding shrubs and 
herbs. What fates do they meet along the 
way, limiting their growth? To understand 
better the process of emergence, IES 
ecologists are looking at factors that affect 
all stages in the life cycles of trees. 
Seed dispersal is the first step in a plant’s 
life cycle and also the first stage at which 
limitation occurs. Under the direction of 
Dr. Mark McDonnell and research 
assistant Judi Koch, seed traps -- devices 
for collecting wind-dispersed seeds - were 
placed at random points along rights-of- 
way. The ecologists are finding that even 
the wind-dispersed seeds don’t travel long 
distances and are thus most likely to land 
near the forest edge. Seedling densities of 
these trees are therefore lower at the 
centers of rights-of-way. 
What happens to seeds once they land at a 
site? Ground-feeding birds and small 
herbivorous mammals such as mice and 
chipmunks can consume large numbers of 
seeds. This seed predation may be a 
significant cause of mortality, one that will 
be investigated by the scientists. Those 
seeds that don’t become lunch for local 
herbivores may germinate, but others will 
rot or die first, reducing the viable 
population even further. Finally, whether 
or not seedling establishment occurs 
depends upon how well individual plants 
compete with the intact vegetation for the 
nutrients, water and light resources they 
need for growth. 
During the first three years of the study, 
the scientists and their research assistants 
worked at over 50 different sites along 966 
kilometers (600 miles) of high voltage 
transmission line rights-of-way in the area 
served by Central Hudson. From fertile 
lowlands in Dutchess County to rocky 
highlands in the Catskills, they sampled 
the shrub and herbaceous vegetation, the 
physical environment and all tree seedlings 
present. Fascinating and complex patterns 
of seedling invasion were found. Some of 
the patterns are related to the patchwork 
of vegetation types found at a given site, 
while environmental factors (soil moisture 
and nutrients, light levels) and disturbance 
history also appear to be important in 
determining where seedlings occur. 
One final study during the first phase of 
the project addressed the problem of how 
to control those trees that do emerge, 
without using herbicides. Since cutting is a 
likely technique, the scientists asked: What 
is the best time of the year to cut trees 
along power lines? The traditional time to 
cut trees is winter. However, this is also 
the time when energy for tree growth has 
already been stored in the roots, and, since 
most trees along rights-of-way are capable 
of resprouting when cut, regrowth is rapid 
in the spring when the energy is released. 
Dr. Canham and co-workers experimented 
with cutting trees at different times during 
the growth season to determine when 
those reserves had been depleted and new 
energy not yet stored. Lower carbo- 
hydrate levels in the roots should 
lead to shorter shoots the following season 
and regrowth should be minimized. Sprout 
growth is being monitored for two years to 
gauge the effectiveness of this technique. 
Current studies by Dr. Canham and 
colleagues focus on experiments designed 
to test ideas and hypotheses generated 
during the first phase of study. The role of 
interactions with the intact vegetation, of 
herbivory, and of physical disturbance in 
reducing or increasing seedling growth 
and survival are being assessed. The 
breadth of these studies, with their focus 
on many different plant communities and 
environments, makes this investigation 
unique in the study of tree seedling 
establishment. 
The importance of resource competition 
has been difficult to judge in natural 
communities, but Dr. Alan Berkowitz, an 
agricultural ecologist with extensive 
research experience in studying 
competition among crop plants, and Dr. 
Canham are directing competition studies 
along rights-of-way. This summer, tree 
seedlings will be transplanted into intact 
communities to measure how the presence 
of the natural vegetation affects seedling 
growth. Results will be compared with 
those from a “garden plot”, nearby, where 
the seedlings are transplanted into areas 
cleared of vegetation. To complement this 
study, critical resources - the soil 
nutrients, water and light - are being 
Dr. Charles Canham uses an all-sky camera to 
measure the amount of light a seedling receives. 
measured by research assistant Vicky 
Kelly to see if their availability is reduced 
by other plants. Then, by artificially 
providing nutrients, water or light to 
transplanted seedlings in future studies, 
the importance of resource competition 
can be confirmed. 
Jay McAninch, an IES wildlife ecologist, 
will focus on the effects of herbivory on 
seedling establishment and growth. This 
summer, working with post-doctoral 
associate Dr. David Wood, he will study 
the effects of different timings and 
intensities of biomass reduction (leaf or 
branch removal) on tree seedlings under 
different levels of environmental stress in 
a test garden. The scientists will also 
evaluate the impact of herbivory and 
seedling predation on rights-of-way 
vegetation by transplanting tree seedlings 
into many different sites along rights-of- 
way, and then monitoring the natural rates 
and timing of herbivory. In addition, 
important data will be collected on how 
plant communities differ with regards to 
species of herbivores present. 
Seedling establishment often occurs after 
some form of physical or human 
disturbance to a site. Frost heaves or dirt 
bike tracks, for example, might allow a 
plant to become established where it 
would otherwise be shaded and stunted; or 
maybe a deer’s hoof scraping away the 
layer of leaf litter would let a seedling 
reach mineral-rich soil below. Predation 
on a seedling can also be affected by a 
disturbance: while small mammals may 
avoid even the smallest gaps in vegetation 
cover because of fear of predators, deer 
might be more apt to notice an isolated 
seedling growing in that same opening. 
This summer, research assistant Jim Hill 
(see article on page 3 of the Newsletter) 
will survey the types of natural and 
human-induced disturbances that occur 
along rights-of-way. Then, next summer, 
he and Dr. Canham will set up field 
experiments to look at the effects of 
different kinds of disturbances on 
germination, establishment and growth of 
tree seedlings. 
Although sampling and observations go on 
year-round, the most active time for data 
collection on the rights-of-way project is 
spring, summer and fall; the 1988 field 
season began in the last week of March 
and will extend to November. A large 
group of dedicated people is required for 
such an ambitious project to succeed. 
Current full-time staff are Dr. David 
Wood, Judi Koch, Vicky Kelly and Jim 
Hill. The full-time research assistants 
during earlier phases of the project were 
Jon Kays, Karen Kays and Marty Burd. 
This summer Dr. Canham and colleagues 
are hiring up to 12 summer project 
assistants to join this collaborative effort 
to understand the ecology of utility rights- 
of-way of the Hudson Valley. 
