It is often seen on the surface of wood a number of
blue—black or blue—grey patches which were originally absent
but developed later if the wood is kept unseasoned in warm,
humid and unventilated places. Sometimes this colour may be
brownish or purple accompanied by smell. This colour or
stain is technically termed as “Sapstain” as it is more
frequent in sapwood than in heartwood. Initially the stain
appears as a tinyblue spot or a small patch or streak on the
freshly cut surface or the end of a log (1). It gradually
and rapidly spreads and becomes deep-siated if some preven— * ‘
tive measure is not taken. Sapstain does not hecessarily
weaken the wood appreciably but it spoils the appearance and
thus reduces the market value. With dark coloured wood, it
is not as serious a problem as with light coloured wood
where the distinguishable blue colour of the sapstain mars
the beauty of the white or light brown colour of the wood.
Except for a few species ( e*g4, teak and sal ) nearly all
our indigenous species are susceptible to attack by sapstain
to a greater or lesser degree any time between a tree is

felled and the converted timbers are’seasoned. It is obser-
ved that light coloured wood is more prone to the attack of

sapstain and as such it is common with satian (Alstonia
narikeli (pterygota alata), chundul (tetrameles

pitali (trewia nudiflora), kadam(anthbcephalus kadam-
scholaris

nudiflora/, uxcwxd uuuxxxuxa;, itaaaui^auxnocepnaxus Jtaaa
ba)t am(yiengifera* dndica)^uTiem(Mehgifera sylvatica)v, civit
iswintonia floribunda), etc. Most of these species are
industrially important and are used in Bangladesh for the
manufacture of safety match, veneer, tea-chest plywood and
battens, doors and windows etc. As such proper .understanding

of the causes and preventive measures of sapstain are essen-
tial to preserve and optimally utilize, our scarce timber

resources.

After three- and a half year’s work in Bangladesh and •:
Pakistan “(1968—71) , mainly concerned with problems related
to forest protection, the author tries to summarize his
observations on the major problems and to give, his suggestions
for strengthening the factors which enhance the resistance of
the forests against .deterioration.

It is in practice in most of the furniture shops and
allied industries to stain wood with artificial colour either
to hide the defects and imperfections of wood surface or to
imitate and impart the popular colour and shades of teak,
mahagony and other valuable species of wood. By this process
cheap and inferior woods are used for furniture and fixture
with better look. But modern outlook has a strong trend in
favour of light coloured or blonde furniture. This is one
of the many causes for which bleaching of wood is going to
play an important role in furniture and cabinet industry.
Another important reason for bleaching wood is to give an
uniform colour to wood which are finished with clear and
transparent lacquers or varnishes. In some species of wood
the intensity of colour depend#mostly on the maturity of
tree. The colour, even in the same species of different age
groups, varies to suoh an extent that it is practically
impossible to match and produce uniform coloured furniture
pieces or panels out of the wood from different trees.
Besides, individual pieces of wood may be abnormally darker
due to other reasons and may contain mineral streaks and
other blemishes which may be removed or made lighter to
match the surrounding wood.

Forest is an environmental complex comprising of plant
communities, wildlife, soil, air and water. To make the best
use of all these, the practice of multiple use of forestry is
necessary. This includes production of timber and other wood
derivatives, forage and browse for livestock, maintenance of
proper environmental conditions for wildlife, landscape
effects, protection against floods and erosion, facilities
for recreation, production and protection of water supplies,

recreational use is an important one.

At the present time the fore’fets cover 33.5 percent of
Czechoslovak territory. Coniferr-ous species cover 67 percent
of the area, of which >orway spruce takes 47 ’per sent,
scotch pine, 14 per cent, silver fir, 5 per cent, larch and
other conifers, 1 per cent. Board—leaved trees share only
33 per cent, of which 17 percent is taken by beech, 7 percent
by oaks, 2 percent by maples, ash and elm and other hardwoods
and softwoods tree species cover 7 percent.

These investigations were made in collaboration between the
Forest Entomology Section and the Wood Preservation Section of the
Forest Research Institute. The present report is part of the project,
‘Tetermination of suitable methods for control of timber destroying
insects”.

Timbers lying in Timber depots of forests are exposed to
attacks by many different insect species. Some of these were
identified by Plumb (1963) who previously collected wood-boring
beetles in the Chittagong Hill Tracts under a US/AID programme.
Unfortunately none of these identified specimens are present in
the Bangladesh.

Sweeping statements and broad generalisations are enemies

of all scientific enquiry and should be kept within the con-
fines of politics. If the results of a study must be stated

in specific terms to become applicable, it is equally necessary
that the questions posed are specific. And the question if
bamboo areas in the reserved forests should be converted to
plantations is far too general to carry any meaning. It is the
ultimate problem to be approached, but it will be approached
step by step in the following.

The hygroscopicity of cellulose and cellulosic
materials, e.g., cotton, wood, paper, etc., decreases
irreversibly, when they are heated at high temperatures
in a dry atmosphere accompanied by a loss of weight
(Urquhart, 1926 ; Stamm. 1964 j Kollman and Schneider,
1963 5 Salehuddin, 1970)• Several postulations have been
advanced’to explain the phenomenon. Stamm (1964), working
with wood, theorised that hemicelluloses in wood are
converted to furfural polymer which is less hygroscopic
than hemicelluloses, resulting in the overall lessened
hygroscopicity of wood. Kollman and Schneider (1963)
thought that heat induced changes in hemicelluloses and
sintering of lignin are responsible for the decrease in
the sorption capacity of wood. However, none of these
theories explain why pure cellulose also behaves in a
similar manner.

In our forestry practices short rotation is .a new
term. By short rotation we are used to the thinkings of
80 years or 100 years or 120 years — a long-long period.
These were our. rotations in the past. Rotations that were
fixed on the statistical basis of growth and yield. These
days the concepts have changed. Economy has come in between
the growth and yield. This has given birth to rotations
in relation to best and earliest economic return. There

were difficulties in fixing up such rotations. The prin-
cipal one being the lack of reliable and adequate statis-
tical data. There was, however, available in hand an

experience of about one hundred years of artificial rege-
neration. Teak (Tectona grandis), the major species in

our plantations were seen flutting from the age of 4t
years and by the time these are 60 years old their growth
are still there, but the proportionate wastage from this
fluting was beyond any economic acceptability. Basing on
this a group of thinkers in the early sixties decided to
bring down the rotation of teak to 60 years. This is the
story of our first attempt to bring down the rotation. It
has no statistical basis, it has no supporting data, but
it seems logical and has been accepted and adopted.