NREM 301Forest Ecology & Soils

Day 16 – October 9, 2008

1. Tree & Stand Growth – Group Presentations2. Lab Tues – Evaluating communities for wildlife habitat3. Take Home Test next Tuesday

Create a Diagram showing the distribution of soils across a Central Iowa Landscape – briefly describe major identifying features of each soil

Group Activity

12

5 6

78

9 10 11

1243

ConcentricDepression

Elongated Depression

Har

ps

Oko

boji

Stor

den

Web

ster

/Can

iste

ao

Cla

rion

or N

icol

let

Hay

den

Stor

den

Terr

ill Coland Spillville

Hanlon

Create a Diagram showing the distribution of soils across a Central Iowa Landscape – briefly describe major identifying features of each soil

Soil Landscape Model for Central Iowa

Coland-Spillville-ZookAssociation

Hayden-Lester-StordenAssociation

Clarion-Webster-NicolletAssociation

Upland Soils – Clarion-Webster-Nicollet Association

Note: Parent materials – glacial till or local alluviumUpland depressional soil sequence from center out –

Okoboji 6, Harps 95, Canisteo 507Webster 107 - depressional, non-circular soil

Best drained soils – Clarion 138 & Storden 62 but Storden is erodedNicollet – somewhat poorly drained

Upland Hillslope Soils – Hayden-Lester-Storden Association

Parent Materials – Glacial Till, Colluvium, Alluvium, Bedrock

Lester – summit, shoulder, well-drained, loam, formed under savanna vegetation

Hayden – shoulder, upper back slope, well-drained loam, formed under forest

Storden – back slope, shallow loam, well-drained, formed under forestTerril – foot slope, well-drained loam, formed under forest

Coland – foot slope, poorly drainedClay loam along small creeks

Flood Plain Soils Along the Skunk River

Coland-Spillville-Zook Soil Association Flood Plain-Toe Slope

Parent Material –Alluvium

Spillville – blackLoam, moderatelyWell drained

Coland – blackClay loam, poorlydrained

Zook – blackSilty clay loam,Poorly drained

Hanlon – natural levee, sandy loamWadena & Biscay minor soils

Tree & Stand Growth

What is a tree?

Perennial – a large main woody stem & large crown of branches that lifts leaves above competitors.

Large crown – large leaf area.

High evapotranspiration – needsLarge root system.

Competitive strategy – outgrowcompetition.

To maintain competitive edgeNeeds apical & lateral meristems

How does it differ from a shrub?

Develops & maintains one dominant main stem to elevate crown into the upper canopy

What are the two major meristems in trees and where are they located?

NodesInternodes

Lateral meristems –secondary growth

P 3 - Handout

Apical meristems – primary growth

What is a meristem?

Lateral Meristems1. Cambium2. Cork Cambium

(Xylem)

(Phloem)

P 2 - Handout

Cork Cambium

Kinds of buds (Apical Meristems)

TerminalLateral Or Axillary

Dormant buds• Seasonally dormant• Suppressed

Adventitious budsEpicormic Branches Floral

Buds are Apical MeristemsPrimary Growth

Bud Growth PatternsFixed Growth – one annual flush

Free Growth – continuous growth

Fixed

Free GrowthMany Riparian Species P 4 - Handout

Recurrent Growth (Southern Pines)

Bud Activity and Tree ShapeExcurrent – strong apical control

Decurrent – weak apical controlBud Activity and Tree Shape

DecurrentWeak Apical

Control

1 3 years

Many Years

ExcurrentStrong Apical

Control

1 3 YearsMany Years

Bud Activity & Tree Shape

P 5 - Handout

Open Grown Stand Grown

Yearly Shoot Growth PatternsDeterminate growth – terminal bud stays active with strong controlIndeterminate growth – no true terminal bud – weak control or may

become a floral bud or abort

Determinate Indeterminate Result of IndeterminateP 5 - Handout

Types of ShootsLong shoots – normal shoots that elongate annually

Short shoots or spur shoots – short ones that do not elongate

Short or Spur Shoot

Short Shoot Turned Long Shoot

P 6 - Handout

# of Years Leaves are Held

1

2

34