---
title: "Defects during growth phase of trees"
subject: "Civil Engineering Materials"
chapter: 7
key: "semester_3/civil_engineering_materials:timber-defects-growth-phase"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/timber-defects-growth-phase
site: BCT Engineering
---

# Defects during growth phase of trees

Civil Engineering Materials · Chapter 7: Timber

- Asked in: 2081 Bhadra, 4 marks
- Video: [L- 23 Defect in timber, Defect in wood , Types of Defect in timber, Causes of Defect in timber, #bmc](https://www.youtube.com/watch?v=dXZU9P_91p8) — Civil Site Plus
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/timber-defects-growth-phase
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-7

## Question

What are the various defects that can occur in timber during the growth phase of trees?

## Short answer

Defects during growth include shakes (heart, star, cup, radial) from frost or over-maturity, knots from branches, rind galls from branch loss, burls, upsets from wind, twisted fibres, water stain, foxiness and callus.

## Answer

Defects that occur while the tree is growing (from natural forces and growth faults) are:

1. **Shakes:** cracks that separate the fibres along the grain, of several types:
   - *Heart shake:* radial cracks starting from the pith, found in over-mature trees.
   - *Star shake:* several radial cracks running from the bark inward, caused by frost or the sun's heat.
   - *Cup shake (ring shake):* curved cracks along the annual rings that separate one ring from another.
   - *Radial shake:* fine radial cracks from the circumference.
2. **Knots:** the bases of branches embedded in the trunk (live or dead, pin, spike); they disturb the grain and reduce strength.
3. **Rind galls:** curved swellings where a branch was cut off and the bark grew over it.
4. **Burls (excrescences):** abnormal growths on the trunk surface.
5. **Upsets (rupture):** fibres crushed by strong wind or by bad felling.
6. **Wind cracks and twisted fibres (spirality):** due to wind, and spiral growth.
7. **Water stain, foxiness and callus:** water stain is discolouration from contact with water; foxiness is a red or yellow tinge caused by over-maturity or poor ventilation; callus is soft tissue that covers a wound.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Heart shakes are
   A. Cracks along annual rings
   B. Cracks from the bark inward only
   C. Radial cracks from the pith in over-mature trees
   D. Swellings
   Answer: C. Heart shake starts at pith. (Key point: Heart shake)

2. A cup shake is
   A. Radial crack from pith
   B. Surface stain
   C. Knot
   D. Curved separation along annual rings
   Answer: D. Also called ring shake. (Key point: Cup shake)

3. Rind galls are
   A. Curved swellings where a branch was cut and bark covered it
   B. Internal cracks
   C. Fibres crushed by wind
   D. Spiral growth
   Answer: A. Bark overgrows the cut. (Key point: Rind gall)

4. Upsets are caused by
   A. Fungi
   B. Fibres crushed by wind or bad felling
   C. Seasoning
   D. Sawing
   Answer: B. Rupture of fibres. (Key point: Upsets)

## Related in Civil Engineering Materials

- [Defects of timber](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Adefects-of-timber) — Civil Engineering Materials, chapter 7, asked 4×
- [Defects of timber by natural forces](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Atimber-defects-natural-forces) — Civil Engineering Materials, chapter 7
- [Defects caused by seasoning](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aseasoning-defects-timber) — Civil Engineering Materials, chapter 7
- [Growth and structure of exogenous tree](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aexogenous-tree-structure-sketch) — Civil Engineering Materials, chapter 7, asked 7×

## Related in other subjects

- [Types of timber and its defects](https://www.bctengineer.com/question.md?key=semester_6%2Fdesign_of_steel_and_timber_structure%3Atimber-types-defects) — Design of Steel and Timber Structure, chapter 9
- [Pattern lobes and 180° out-of-phase array](https://www.bctengineer.com/question.md?key=semester_6%2Fpropagation_and_antenna%3Alobes-importance-opposite-phase-array) — Propagation and Antenna, chapter 2
- [L-G fault and 3-phase fault, 30 MVA generator](https://www.bctengineer.com/question.md?key=semester_5%2Fpower_system_analysis_ii%3Alg-fault-30mva-voltages-3phase) — Power System Analysis II, chapter 5
- [Activities in the initiation phase](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Ainitiation-phase-activities) — Project Engineering, chapter 1