An article I wrote:
COLD WEATHER COMFORT
Spend the winter working warm
by Tom Dunlap
One of the reasons that people enjoy arboriculture is that we get to work
outside all the time. On most days we are the envy of the office-bound world.
On other days though many treeworkers would rather be inside chasing paperwork
instead of deadwood.
When the weather starts to cool off in September I start to look forward to
the seasonal changes that I know are coming. Among the changes I wait for are
the glorious colors that were masked by the green in the leaves, no bugs, the
chipper truck not filling up so quickly because we aren't hauling leaves, and
not having sweat dripping into my eyes. At the same time the trees are
changing their wardrobe I change mine. The trees change from green to fall
colors and then bare limbs. In the fall, my wardrobe changes from T-shirts to
long sleeved turtle necks and fleece sweaters.
Since the early eighties our trade has gone out to other disciplines within
the vertical world for tools and techniques. Gone are natural fiber ropes and
rigging in natural crotches. Now we have ropes of many colors, strengths, and
specific purposes. Look inside arborist's tool boxes these days and there
will be carabiners, slings, and lowering devices that mountaineers or high
angle rescue crews would use.
Arborists have become very adept at borrowing and adapting the tools for our
use. Now it is time to adapt and borrow the clothing used to stay comfortable
outside from the mountaineers. The advances in fiber design are not limited
to ropes and slings. The synthetic fibers used to make clothing can keep
treeworkers warm, dry, and productive better than any of the natural fibers
worn during the summer. We demand high performance and durability from our
tools and machines. Now we can get that same high performance from our
clothing.
The measure of "cold" relates mostly to your personal comfort zone and what is
usual for your town. The winters that I work in here in Minneapolis are a lot
different from the winters that my tree climbing friends have down in Austin,
Texas. In Australia there is a draft standard for tree climbing in adverse
weather. When the air temperature or wind chill is below 41 degrees F, they
advise taking extra safety precautions. The wind chill takes into account the
air temperature and wind and what that would feel on like on bare skin. Zero
degrees is zero degrees, but if you have a good attitude and the right
clothing you will be on your way to being comfortable.
There are several ways that we lose heat. When our muscles work we produce
heat given off by radiation. This excess heat is conserved most easily by
wearing a hat. Almost half of our heat is lost from an uncovered head.
Convection comes into play when the wind blows the heat away. When climbing
in leafless trees it is hard to stay out of the wind. Wearing windproof
clothing will help here. Grabbing onto aluminum chainsaws and frozen tree
limbs will conduct heat out of our hands quickly. By wearing too many clothes
and breaking a sweat we can get chilled by evaporation. The heat of our body
is used to keep the sweat vaporized and this is also a major heat loss. When
we inhale cool, dry, winter air to our warm, wet lungs, a little moisture is
exhaled with every breath. When I go winter camping I know that if the night
is going to be below zero, I will respire over a pint of water while sleeping.
During the winter work day you can count on needing as much or more water than
you needed during the summer.
The two keys to staying comfortable in the summer are staying dry and venting
excess heat. Here is where we can take some lessons from the mountaineering
crowd. Most people have heard the advice over the years to dress in layers.
What is more important is to use the correct materials in the layers of
clothing. Do you know what the saying "Cotton Kills" means? Cotton is a
great, inexpensive material for clothing but when it gets wet, the water
saturates the fibers and in order for your body to stay warm, you have to pump
many calories of heat into the water to get it to vaporize. This leads to
cooling, and in extreme cases, death. The synthetic fibers are hydrophobic.
Water does not "stick" to them. The water droplets will hang on the fibers
like dew on a spider's web. Many fewer calories re needed to vaporize that
water and push it into the outer layers of clothing. Wool is a good choice
for clothing except that some people get itchy from coarse wool. Silk long
underwear is not as durable as the synthetic fibers.
Against the skin wear a set of underwear blended from polypropylene,
polyester, or acrylic. These fibers will move the sweat away from your skin
into the insulation layer. Next, the insulation layer should be durable,
lightweight, and breathable. These days you can't go into a clothing store
without seeing racks of fleece clothes. Wool performs well in this layer, but
fleece works better. A wet layer of wool will be heavy and takes a long time
to dry on your body. I have worn wet fleece clothes and as long as I stay
moving, I can be warm. Besides the performance of fleece, most of the clothes
look good. There are fleeces made now that are wind and water resistant too.
The outer layer of clothing is for protection. Keeping the wind from blowing
heat off our body as well as keeping us dries inside and out is what we can
expect a good jacket to do. My Dad was a letter carrier and he used to say
that you are going to get wet from the inside or the outside. Many years ago
that was true. Now there are many waterproof-breathable fabrics available.
Those two factors are important, but I have found that wearing jackets that
have vents built into the arm pits or between the shoulders is more
beneficial. Being able to vent the excess heat that we can generate
footlocking up into the tree is going to pay off by not having our insulating
layer wet. Then, once the climber is in the tree doing less strenuous work,
it is time to close down the vents and contain our heat.
After spending time working and playing in Minnesota's winters I have found a
few useful strategies for being comfortable outside in any weather. Starting
at the top, I carry several different hats. All the headgear is synthetic but
the hats provide varying amounts of insulation. A lot of times using just an
earwarmer under my helmet is all that is needed. When the conditions are a
little more severe I wear a balaclava (not the pastry). These hats some down
over your neck and have a cutout for your face that can be drawn up so that
only your eyes are exposed or tucked under your chin to open your face. Neck
gaiters add a little insulation and are much safer than having a long scarf
trailing around. Turtle neck shirts that have zippers down the front to allow
excess heat to vent to the air, keeping your clothes dry. A good source of
tough clothing is to look for snowboarding gear. The outer shells are
generally cut a little fuller to allow for more insulation and easy arm and
leg movements. The bibs that I use have heavy nylon knees and seat to reduce
wear and tear. I like the bibs for climbing because I can tuck my jackets
into the bibs, put on my saddle, and my shirts don't come untucked while
climbing.
Keeping hands and feet warm is the biggest challenge in the winter time. If
you start to get cold hands and feet, put on a hat or hood, or change to a
heavier one.
Since we loose so much heat out of our head that is an easy way to reallocate
the extra heat. There are shirts made that have longer sleeves that cover the
palms. The shirts will have a cutout for the thumb so that the sleeve stays
in place. To keep your hands warm try wearing a light pair of synthetic liner
gloves so that you never have bare skin exposed. If you work with two pairs
of gloves and keep the extras stuffed inside your shirt you can change gloves
and dry out the wet ones inside your tummy oven. A tip that I picked up from
some Arctic explorers is to keep your knees warm so that you keep your feet
warm. When the warm blood is pumped to the feet if comes out of the muscular
thighs and passes through the bony knees. There is no insulation in the bony
knees so insulating the knees helps to keep your feet warm. Wearing knee pads
or doubled leg warmers is beneficial. The hard shell pads from in line
skating or volleyball pads have been used.
When you go to Hawaii you are given a lei. When you come to Minnesota in the
winter, you are given pac boots. These boots have rubber lowers and leather
uppers. The liners are made of thick wool or synthetic felt. One way of
keeping your feet warm that may sound funny is to wear vapor barrier liner
(VBL) on your feet. What these do is keep the sweat from your feet from
saturating your insulating socks and boot liners. After putting on a pair of
light synthetic socks, you slip on the VBLs and then your heavy socks. At the
end of the day you will not pour out a puddle of sweat from the VBLs. When
the air around your feet is saturated, the sweat glands stop working. There
are specially made coated nylon socks. Most of the time I go low tech and use
old bread bags. My suggestion is to try this out on seperate feet so that you
have a comparison. In the morning, put the VBL on one foot and the same socks
on the other without the VBL. Go to work and forget the VBL. At lunch you
should be able to tell a difference. If you are going to be inactive for a
long time, it would be useful to have a spare pair of liner socks to change.
End of part 1