Species composition, density and gross volume of forest stands and condition of standing trees (lopped, girdled)

The details of data usedwere as follows:

• Northeast aspect ³⁹

plots

October 1998

• Southwestaspect ³⁷

plots

October 1998

• Asinabari forest 20

plots

October 1998

Thetreevolumewasobtained fromtheLocal VolumeTableof

Wangdigang

^Forest

Unit, prepared by

the Forest Resources

Management

^{Divisionin 1993.For}

Castanopsis,

^Persea

and

Quercus,

^individual local volumetariffswereused, whilefor other genera, the^vol¬

umetariff for hardwood

species (combined)

^{was consulted.}

2.2.5.3

Vegetation

^assessmenton the northeast and southwest

aspects

^at the same season

The state and

availability

^of

ground vegetation,

^tree

seedlings

^and

saplings

^{atthe same}

season were

compared

^intwo aspects^ofthe

study

area, northeast andsouthwest. Thefol¬

lowing

combinations of datawere

analyzed:

• Northeast aspect

(39 plots)

^{vs. southwest}

aspect (37 plots)

in October 1997

• Northeast

aspect (39 plots)

^{vs. southwest}

aspect (37 plots)

^{in March 1999}

The northeast andsouthwest aspects^{were considered tobetwo}

separate samples.

^Differ¬

ences in themeandensities of_grasses

(by

all grass

total),

forbs/shrubs

(by total),

^small

tree

seedlings (by total), damaged seedlings

^and

saplings (by total)

^and

seedlings

and sap¬

lings (by

^total)between thetwoaspects^were

compared using

^two

samples

^ttest

(p=0.05).

34

2.2.5.4 Effects of

altitude,

^{tree crown} cover, cattle

tracks, lopped

^{trees and}

cowsheds on

ground vegetation

^and

seedlings

During

^the

inventory,

^otherparameters^{wererecordedonthe}

plots,

^aswellas

counting

^and

measuring ground vegetation, seedlings

^and

saplings.

^{Thesewere altitude, treecrown}

coverandpresence of

lopped

trees, cattletracks andcowsheds within a 50meterradius of every

plot.

^Theassociation between these recorded

parameters

^was

analyzed

^acrossthe

sites:

ground vegetation, seedlings,

^{altitude, tree crowncover, cattle tracks,}

lopped

^trees and cowsheds.The dataof all siteswascombined and correlation

analyses

^were

produced

for 96

plots.

• Northeast aspect ³⁹

plots

^{October 1997}

• Southwestaspect ³⁷

plots

^{October 1997}

• Asinabari forest 20

plots

^{October 1998}

2.2.6 Socio-economic survey

The aims of the socio-economic survey^{were to}

gain

^an

insight

^{into the}

following:

• Social andeconomic needs and

priorities

^ofthe farmers

• Traditional

grazing practices

and livestock andthe

Tsamdrog

management system

•

Perceptions

^{of forest}management

practices

in relation toforest

grazing.

The

following

three methods wereused:

• Household surveys

• Field observations and

key

informant interviews

• Transect survey of

Tsamdrogs.

2.2.6.1 Household survey

Informationon socio-economic conditions and

people's

^{needs and}

perceptions

^wascol¬

lected

through

^a household survey^basedon structured

questionnaires (Appendix I).

^All

25households which used the

study

^{areaforwinter}

grazing

^were interviewed. Thesecon¬

sistedof 18 householdson the southwest

slope

^{and sevenhouseholds on} the northeast

slope

^ofthe

study

^{area.The 18 householdson the southwest}

slope represented

^{9% of the}

total households in

Geyling Geog,

whereas the sevenhouseholdsonthe northeast

aspect represented

^{2% ofthe} households in

Bongo Geog

^{and 17% of}the households in Gedu/

Trashigang village.

Personal visits weremadetothe cowsheds inthe forests

(study area)

tofillin the

questionnaires.

Those cowshedsnearthe roads werevisited

first,

^{with other} cowsheds visitedlater, after theirlocationhad beendetermined

through inquiries.

^This

methodwas used because herders and their household

members, especially

^{onthe south¬}

eastaspect, ^live in the cowsheds

during

^the

period (winter)

^when

they

^{arein the}

study

^ar¬

ea.The choiceof

respondents

ⁱⁿthe householdswas

kept

open. One of any adult member in thehouseholdwas interviewed

during

^{visits in thecowsheds.}

The socio-economicinformationcollected

though

the household

questionnaire

^{was asfol¬}

lows: number of persons in ^ahousehold and theirsex ratio,number of children

attending

school,

number of cattle

by breed,

number of milk_cows, land

holdings by

category,^im-

portant^household

activities, production

^of

dairy products

^{and income}

through

sale of the

dairy products.

The information

pertaining

^to

grazing practices

^and

Tsamdrog

manage¬

mentwas asfollows: number andnames of

Tsamdrog

^tractsof which the householdowns

the

rights,

^the

period they

^are

grazed,

traditional methods of

Tsamdrog utilization,

^when

herds

migrate

^{to summer}

grazing grounds, forage

situation andreasons for

shortage

^of

forage. People's perceptions

^of

grazing damage

^to

seedlings

^and trees,

changes (good

^or

bad) brought

^about

by forestry operations,

situation of forestresources in theareaand the purposeforests are

expected

^{to serve were alsocollected}

through

the household survey.

The

Dzongkhag

^{termsareusedforthe land}

holding category

^andtheir

English equivalents

are

given

ⁱⁿ

Appendix

^IV.

2.2.6.2 Field observations and

key

informant interviews

To

supplement

the household survey, various

aspects relating

^toforest

grazing

interaction

(e.g. grazing preference by

cattle within the

forest, lopping

^{offoddertrees,} clearance of

undergrowth)

^wereobserved inthe field

during

^thecourseof the field

inventory.

^The

key

informants

(agriculture

^and

pasture

^extension agents^and

foresters)

^{wereconsultedtoval¬}

idate information furnished

by

herders andfarmers. Information onthe cattle

population

wascross-checkedwith the cattlecensusof the

Geog provided by

^the

Dzongkhag

^admin¬

istrationtodetermine _any

trends,

^asinformation onindividual

villages

^{wasnotavailable.}

Inthe

field,

information

given by

^a

particular

^{herderwasverified}

by asking

^his

neighbors

and vice versa.

2.2.6.3 Transect survey of^a herder's

Tsamdrog

Tsamdrogs

^{in the}

study

^{area are}

heavily

^utilized

by

cattle from Novemberto

March,

^while

mostarenot used from

April

^to

October,

^{as cattle}

migrate

^tothe

higher

^altitude

grazing grounds during

^this

period.

^Noinformationwas available on the state of

forage

^{in the}

Tsamdrogs

^{in these two seasons.This} information wouldfacilitate

regulation

^{of cattle}

grazing

ⁱⁿ

Tsamdrogs, according

^to

forage availability. Accordingly,

^thetransectsurvey

wasundertakentoestimate the coverage ofgrassesand forbs/shrubs in October 1998 and in March 1999. One of the best

Tsamdrogs

^was

selected,

^locatedon the southwest

aspect

ofthe

study

^{area. A transect line}

ascending

from 1800 maslto 2000masl was laidout acrossthe middle of the

Tsamdrog.

^The

starting point

^{wasselectedatrandomatthelowest}

point (1800 masl).

^{One lnr-}

plot

^{waslaid out}every 10^meters

along

^{thetransect lineus¬}

ing

^afixed compass

bearing (80x).

^A visual estimate oftheareacovered

by

different veg¬

etationtypes

(grass,

^forbs,

litter/brush,

^bare

ground)

^{in the}

plot

^{was then}

made,

^{and the} coverage^value

assigned (in percentages).

^The

height

^ofthefive tallest grasses in every

plot

^was measured. Intotal, 39

plots

^{were laidout in the}

Tsamdrog

ⁱⁿ October 1998. The

transectwasre-cruised in March 1999 and

only

³⁴

plots

revisited. Since

only

^the

starting point

^{of thetransectlinewas}

^fixed,

^{andnot the}

plot,

^{the second}measurementswerenot taken atthe exactspotof the first measurement. Given this

limitation,

^{thetwomeasure¬}

ments

(plots)

^{atthe twoseasonswereconsideredastwo} separate

samples

^{in the}

analysis.

Differences in themean

heights

^ofgrasses in thetwo seasons were

compared using

^two

samples

^ttest

(p=0.05).

36

2.2.7 Assessment of forest

planning

^methods

The available documentation onforestmanagement

planning

^{in Bhutanwasstudiedtoas¬}

sess the status of

present forestry planning.

^In

particular,

^{thecontents of theforest man¬}

agement

plans

^and

inventory

^{methodswerereviewed.}

Legal

^and

policy

^sources

relating

toforest

planning

^{inBhutan, suchasthe LandAct}

^1987,

^theForest

policy 1974,

^theDraft

Forest

Policy

^1991, the Renewable Natural Resources

(RNR)

^Sector

Policy 1991,

^theFor¬

est

Development

^Plan 1992 and the Forest and Nature Conservation Act 1995 wererefer¬

enced.

Assumptions

^weremade from the

legal

^and

policy

^{bases to elaborate a}

planning

concept^forbroadleaf forest management.

Existing

^{literature onforest}

planning using

multi-use concepts^{and the}

strategies

^to

integrate grazing

^{in forest}

planning

^werealsoex¬

amined.

The forest inventory: ^{results and discussion}

3.1 Assessment of

vegetation

^onthe northeast

aspect

^{of the}

study

^area

in October 1997 and March 1999

3.1.1 Ground

vegetation

Forbsand shrubswerethedominant

ground vegetation

in October 1997 and March 1999.

The number ofshrubsandforbswas

higher

ⁱⁿOctober 1997 than in March

1999,

^whereas therewerefewer grasses in October 1997than in March 1999. Therewas nodifferencein the number ofsmall tree

seedlings

^{recordedinOctober 1997 and March 1999}

(Figure 3.1).

80

> 60

</>

c

<u a 0)

>

cc 40

20

0

HShrubs/forbs Grasses

H Smalltreeseedlings

October 1997 March 1999

Figure ^{3.1 Ground} vegetation^onthe northeastaspectin October 1997 and March 1999.

3.1.1.1

Grasses

Digitaria, Paspalum, Kikiyu

^and bamboo make_upthe _grass

population. Paspalum

^and

Digitaria

^arenative grasses

prominent

in open meadows ^and forest

clearings. Kikiyu

^is

anexotic grass, which is

gradually spreading

into open^meadowsand forest

clearings.

^The

bamboo recorded is a

spiny-noded

Chimonobambma callosa that occurs atloweralti¬

tudes. Thenumberof

Paspalum

recorded in March 1999was

significantly higher

^thanin

October 1997

(Figure

3.2 and Table

3.1).

In the October 1997 enumerationanumberof

Paspalum

^wereoverlooked which

explains

^this

unexpected

result. Therewas nota

signif¬

icant difference inthenumber of

Digitaria, Kikiyu

and bamboo recorded in October L997 and March 1999. The same was trueofthetotal number ofgrasses recorded in October 1997 and March 1999

(Table 3.1).

38

ns

c3

o o

30 25 ^- 20

>. 15

m

S 10 a

5 0 ^{-..^}

h

- ] ^October ¹⁹⁹⁷ D March 1999

Dgitaria

{,,.

Baspalum Kikiyu Grasstypes

M—I

Bamboo

Figure^{3.2 Grasses}by type^onthe northeastaspectⁱⁿ October 1997 and March 1999.

Grasses October 1997

df=38

March 1999 df=38

t-value P

Digitaria 30,000 26,219 ^{0.63 0.54}

Paspalum 12,308 18,205 ^{2.39 0.02}

Kikiyu 7,821 2,308 ^{1.06 0.29}

Bamboo 3,013 2,821 ^{0.55 0.58}

TOTAL 53,525 49,551 ^{0.46 0.65}

(Boldpvalue=significant, df=degree^offreedom)

Table3.1 Pairedsamples^{t testonmean}

density

of grasstypes(no

ha"1

₎forOctober 1997

vs March 1999 with 39plots^{on thenortheast}aspect.

3.1.1.2 Forbs/shrubs

Thetotal number offorbs/shrubswas

significantly higher

in October 1997 than in March 1999.

Significant

differences in the total number offorbs/shrubs

during

^{the two seasons}

were due to the

palatable

group, which^{had been}

considerably

^reduced

by

^{March 1999}

(Figure ^3.3).

^{This drastic reduction was aresultofa}

significantly

lower numberof

Apor-

osa, Viola and Pilea recorded in March 1999

compared

^toOctober 1997

(Table 3.2).

^The number of Pteridium recorded inMarch 1999wasalso

significantly

lower than in October 1999. It was also noted thatRubia, Rubus, Solomon, Persicaria, Labiatae, ^and

Aporosa

recordedinOctober 1997 had

disappeared by

March 1999. These may^have eitherbeen browsed off

by

^{cattle or}have withered in the winter.

î

150 3

o o C 100

>.

0 [~-

Palalable Unpalatable ^Others Group

Figure

^3.3 Forbs/shrubs

by

group^{onthenortheast} aspectin October 1997 and March 1999.

Genus October1997

df=38

March 1999 df=38

t-value P

Palatable

Viola 21,666.70 8,461.56 ^{3.15 0.001}

Pilea 64,358.97 22,243.59 ^{3.00 0.01}

Aporosa 32,371.80 ^{000 2.39 0.02}

Rubus 961.54 0.00 1.92 0.06

Persicana 16,474.36 ^{0.00 1.85 0.07}

Aconogonon ^{448.72 448.72 0.00 1.00}

Labiatae sp. 2,051.28 0.00 1.00 0.32

Rubia 128.21 0.00 1.00 0.32

Solanum 64.10 0.00 1.00 0.32

Elatostema 59,679.49 59,679.49 ^{0.00 1.00}

Unpalatable

Ptericanthus 7,307.69 ^128.21 1.14 0.26

Plantago 10,576.92 5,897.44 ^1.05 0.30

Pteridium 29,679.50 19,935.90 3.34 0.001

Rumex 0.00 64.10 1.00 0.32

Others

Lycopodium ^{256.41 64.10 1,00 0.32}

Rouwolfia 0.00 320.52 1 00 0.32

Unknown 3,846.15 0.00 1.02 0.32

TOTAL 249,871.84 117,243.63 265 0.01

(Boldpvalue=significant,

df=degree

^offreedom)

Table 3.2 Pairedsamples ^{t teston mean} densityof forbs/shrubs (no

ha"1)

bygenus^for October 1997vs March 1999with 39 plots^onthe northeastaspect.

S October 1997

j

March 1999

I

^

40

3.1.1.3 Small tree

seedlings

The

pioneer

group dominated the smalltree

seedling population

while the primary and

secondary

groups formed small

populations

^{atboth seasons}

(Figure

³

A).

^{Thetotalnum¬}

berofsmall tree

seedlings

^recordedinOctober 1997 andMarch 1999 didnotdiffer

sig¬

nificantly (Table 3.3). Furthermore,

^the

ingress

^and

mortality patterns

^{ofsmall tree}

seedlings

observed inthe two seasonsdid not follow atrend. Some

species

^likeFicus,

Daphniphyllum,

^Glochidion and Casaeria whichwere documentedinOctober 1997 had

disappeared by

^March

1999,

^while

Castanopsis

^{and Maesa, which werenot} recorded in October 1997 had

appeared by

March 1999.InOctober 1997therewas

only

^asmallnum¬

berof

Walsura,

but this hadincreased

considerably by

^{March 1999,} whereas the number of

Eurya

^haddecreased

significantly by

^{March 1999}

(Table 3.3).

Primary Secondary ^Pioneer

Group

Figure^{3.4 Smalltree} seedlings bygroup ^onthe northeastaspect^{in October 1997and} March 1999.

Genus October1997

df=38

March 1999 df=38

t-value P

Primary

Acer 128.21 64.10 1.43 0.16

Beilschmiedia 192.31 0.00 1.36 0.18

Cinnamomum 320.62 128.21 1.14 0.26

Castanopsis ^{0.00 128.21} 1.43 0.16

Persea 64.00 577.00 0.90 0.38

Secondary

Ficus 192.31 0 00 1.78 0.08

Glochidion 64.10 0 00 1.00 0.32

Macropanax ^384.62 128.21 0.89 0.38

Pioneer

Table 3.3 Paired

samples

^{t teston mean}

density

^{ofsmall tree}

seedlings

(no

ha"1)

by genus forOctober 1997vs March 1999 with 39 plots^on the northeastaspect.

Genus October 1997 df=38

March 1999 df=38

t-value ?

Eurya

^{3,397.44 320.51 3.09 0.001}

Walsura 64.10 2,307.69 3.33 0.001

Maesa 0.00 64.10 1.00 0.32

Daphniphyllum ^{256.41 0.00 1.67 0.10}

Casaeria 384.62 0.00 1.64 0.11

Symplocos

^{2,500.00 1,858.97 0.68 0.50}

Viburnum 384.62 256.41 0.57 0.57

TOTAL 8,333.36 5,833.41 ^{1.57 0.12}

(Boldp

value=significant, df=degree

^offreedom)

Table 3.3 Paired samples^{ttest on mean}

density

^{of smalltree}

seedlings (no ha"1) by

genusfor October 1997vsMarch 1999 with39plots ^onthe northeastaspect.

No documento Cattle grazing - an integral part of broadleaf forest management planning in Bhutan (páginas 34-42)