Lecture 3 (1) From crops to the jungle

Definition of tree

A woody plant with usually a single stem growing to a height of at least 2m

Or if multi-stemmed, then at least one vertical stem 5 cm in diameter at breast height

Definition of forest

A large area covered chiefly with trees and undergrowth

• Land spanning more than 0.5 hectares with trees higher than 5 meters, and a canopy cover of more than 10%

• Include land that’s predominantly under agricultural or urban land use

Primary or natural forest

Naturally regenerated forest of native species, where there are no clearly visible indications of human activities and the ecological processes are not significantly disturbed

Forest estate

All the land containing a forest endowment

Forest stand

A continuous piece of land covered by a relatively homogeneous forest type

Forest plot

A polygon, usually circular and small (e.g. 300 m^2) where all trees are measured to estimate stand- or estate-level forest metrics

Afforestation

Establishment of forest through planting and/or deliberate seeding on land that, until then, was not classified as forest

Reforestation

Re-establishment of forest through planting and/or deliberate seeding on land classified as forest

Deforestation

The conversion of forests to another land use, or the permanent reduction of tree canopy cover below the 10% threshold (degradation)

Variables affecting climate and microclimate

(deal spats)

Distance to water bodies

Elevation

Atmospheric pressure

Latitude

Surface albedo

Precipitation magnitude & type

Air temperature

Topography

Solar radiation

What summarizes everything (variables affecting climate cand microclimate)

Air temp.: Avg. amd variation

Precipitation: Sum and variation

World biomes

The type of vegetation present in an area depends on climate, which is summarized by temperature and precipitation (averages and seasonal variation)

Biome

Very large areas of the Earth’s surface that have similar climates and vegetation

Formation

Community with a specific vegetation structure (e.x. Cold desert or temperate deciduous forest), also used as a subdivision of biome

Growth form

Types of plant such as trees, shrubs, herbs, epiphytes (non-parasitical upon another plant), lianas (woody vines), and bryophytes (mosses & lichens)

Factors that affect forests: Human

Degradation

• Defaunation

• Fragmentation

• Illegal logging

• Invasive species

Deforestation

• Agricultural conversion

• Urbanization

• Mining

Factors that affect forests: Natural

Abiotic

• Fire: Superficial, Canopy

• Water: Flooding, drought

• Temperature: Heat, frost

• Snow/Ice: Avalanches, physical damage

• Wind

• Geomorphic: Landslides, volcanic eruptions

• Earthquakes

Biotic

• Insects: Defoliators, Wood borers & bark beetles

• Pathogens: Virus, bacteria, fungi

• Tree fall

• Vertebrates

Forests in BC

BC has Boreal, Coastal, Columbia, Montane, and Subalpine

Biogeoclimatic zone

A geographic area having similar patterns of energy flow, vegetation, and soils as a result of a broadly homogeneous microclimate”

Developed by Vladimir Krajina from UBC in the 1960s and 1970s

Each zone has subzones related to precipitation and temperature: IDFdk means INterior Douglas fir day (d) and cool (k)

According to FAO, a fast-growing industrial ___

IS a forest

The industrial plantation is the best type of forest to use TRIAD

Planted forests by objective

• Timber production: Ex. Pinus radiata plantations in New Zealand

• Non-timber products and services: Ex. Maple syrup plantations in Vermont

• Protection and restoration: Soil erosion control in South Korea

Planted forests by timber product

• Pulp: Ex. Eucalyptus

• Fiber and particle boards: Ex. Pinus patula plantation

• Solid lumber (wood): Ex. Teak plantation

• Veneer: Black walnut plantation

Specialty plantation

Bamboo plantation

Not forestry

Fruits

Palm oil

Cork

Additional ___ million ha of plantations are required to supply 100% of global timber (It’s ___ million ha now)

371, 204

Wood supply from plantations is expected to reach __% of total by 2050 (It’s __% now)

60, 35

Classification criteria (Characteristic: Predominance in natural vs. planted forests)

Regeneration type: Natural vs. planted

Age: Multi-age vs. contemporary

Tree species: Multiple vs. single

Harvesting age: Undefined, long s. defined, short

Management intensity: Low vs. high

Harvesting method: Selective vs. clearcutting

Biodiversity: High vs. low

Species origin: Native vs. exotic

Tree density (Nha)

Trees/ha

Number of trees in a hectare (typically extrapolated)

An area-level metric

Synonym is stocking density

Diameter at Breast height (DBH)

A linear measurement (cm or in), representing the diameter of the tree at 1.3 meters above the ground

Height (H)

Tree height from the ground to highest top

Basal area

Cross-sectional area of a tree trunk at breast height (typically 1.3 meters or 4.5 feet above the ground) (m²/ha)

At the plot or stand level, G can be expressed as basal area per hectare (Gha) (m²/ha) sum of the basal area of all trees in a hectare (typically extrapolated)

Volume (V)

m³ Timber ___ from ground to tip

Volume per hectare (Vha)

(m^3/ha): Sum of timber volume of all trees, extrapolated to ha

Total volume (Vt)

(m^3): Total timber volume in a given stand (m^3/ha x ha)

Merchantable volume

Volume excluding stump (e.g. 30cm height) and treetop (ex. Less than 10 cm in diameter)

Individual tree (direct) multiscale

• Species

• DBH

• Height

• Notable defects

→ Individual tree (processed)

• Basal area

• Volume

Plot multiscale

• Stocking density

• Basal area

• Forest cover (%)

• Dominant height 

• Volume (m^3/ha)

Stand and land totals

• Area (ha)

• Volume (m^3)

• Commercial value ($)