FONDECYT

Basic wood characterization

General data *

  • Common/commercial name: Roble, Pellín
  • Native name: Pellin, Koyam
  • Scientific name: Nothofagus obliqua
  • Foreign name: Patagonian Oak, Roble de Neuquén, Roble Beech
  • Family: Fagaceae
  • Location: Central Zone, South Zone

Description of the species *

Deciduous, leafy tree with thick branches. It reaches a height of up to 40 meters and its trunk measures about 2 meters in diameter. Juvenile individuals are called “hualle”, where the sapwood predominates, whitish and “pellín” to adult specimens where the heartwood, reddish brown, has a greater presence. The bark of the pellín is thick, cracked and dark gray, while in the hualle it is smooth of whitish gray color. It has a natural durability of more than 15 years in exterior uses. It is classified as highly resistant to specific fungal attack.

It is present in the national parks Radal Siete Tazas, Nahuelbuta, Huerquehue and Villarrica; and in the national reserves Los Ruiles, Los Queules and Los Bellotos del Melado. Its name is due to its relative similarity to the European Oak (Quercus robur) which led the Spanish conquerors to give it that name.

Visual characterization

  • Main color Dark brown
  • Secondary color Reddish brown
  • Color of grain Reddish brown
  • Grain definition Well defined
  • Grain shape Irregular
  • Grain spacing Fairly widely spaced
  • Grain thickness Intermediate
  • Presence of knots Some knots
  • Natural gloss Very little
  • Porosity No pores
  • Texture Slightly smooth
* The data in the sections with an asterisk in their title were compiled from various bibliographic sources listed at the bottom of the page. All other sections present exclusive information obtained through the development of this project.

The concepts of “main color” and “secondary color” in the visual characterization correspond to the so-called spring wood, lighter and fast growing, and the “grain color” to the summer or late wood, darker and more compact due to its slow growth. This difference generates the tree's growth rings and grain patterns, determined by the type of wood cut. It should also be noted that while some species produce wood that is uniform in color and hardness throughout the tree trunk, others have differences between the sapwood (outer layers of the trunk) and the heartwood (center of the trunk), the latter being darker and more solid.

Microphotographs of the species (1600x)

Physical/mechanical characterization

General data (humidity 12%) *

Hardness (N = Newton)
  • Parallel 4949.00 N
  • Perpendicular 4557.00 N
Tensile strength
  • Radial 6.08 N/mm²
  • Tangential 6.08 N/mm²
Flexural strength
  • MOR 82.03 N/mm²
  • MOE 12112.80 N/mm²
Density
  • Density 624 kg/m³
  •  
Compressive Strength
  • Parallel 46.65 N/mm²
  • Perpendicular 22 N/mm²
Shear Strength
  • Radial 11.76 N/mm²
  • Tangential 11.76 N/mm²

Suggested applications and uses from the technical point of view *

Experiential Characterization

Sensory level: feel and perception

N per species ≈ 60

Semantic differential

This kind of graph defines, by means of a list of ten pairs of opposite concepts, how people perceive, and therefore, how they describe a specific wood, in this case from the sensory level, i.e., using the five human senses. It also allows a quick visual comparison with the results of the other woods under study.

Affective level: Emotions and affections

10
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
10
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
High intensity
High unpleasant activation
Negativity
Low unpleasant activation
Low intensity
Low pleasant activation
Positivity
High pleasant activation
N per species ≈ 60

Circumflex of emotions

Emotions can be organized into a circumplex by their intensity and positivity or negativity (review literature sources section for more detail). This allows a better understanding of affective experience. The most frequent coincidences (3 or more mentions) in the emotions reported by people with respect to each species are shown. The name and number of mentions each emotion had can be seen by positioning the cursor over each circle.

N per species ≈ 60

Balance of positive and negative emotions

This graph shows the total number of emotions that people reported experiencing when interacting with each wood species, and the percentages of positive and negative emotions out of that total.



Interpretive level: meanings and associations

N per species ≈ 60

Semantic Differential

This graph defines, by means of ten pairs of opposing concepts, how people perceive each wood, in this case interpretively, i.e., according to the meanings and associations they attach to each species. It also allows a quick visual comparison with the results of the other woods under study.

N per species ≈ 250

Free association of words

Materials possess meanings that are related to our previous experience, culture, background, etc. People freely associated the different woods with words that arose spontaneously to them. The words that were repeated most frequently (3 or more mentions) and the number of times they appeared are presented.

Biometric measurement of the experience

Imotions eyetracking

N per species ≈ 100

Level of gaze fixation on the species in a given time (seconds).

Using specialized eyetracking software and equipment, we defined how long people fixated their gaze on a specific point. The graph shows how many seconds, in total, each species was observed by showing them all together (for 45 seconds) to a total of 100 people (one person at a time). The positions of the woods were changed during the process to avoid significantly influencing them.

Heat map


Heat map: gaze fixation on each species

Using the same eye-tracking tools, "heat maps" are created, which clearly show those species on which people tend to fixate their gaze the most (500 milliseconds or more looking at the same point) and how those fixations are distributed among all of them. The areas where the gaze of the 100 people (one at a time) fixated the most (though not necessarily the longest) while looking at all the woods for 45 seconds are highlighted in warmer colors.


Imotions facereading

N per species ≈ 60

Average emotions experienced during the time of interaction with the wood according to software

The specialized software Imotions and its facial gesture reading module were used. Using an HD camera the software can capture people's micro-expressions while interacting with wood and translate them into these seven predefined emotions. The graph presents the average in which people showed these emotions when exploring the species with all their senses for thirty seconds.

Value
Seconds
N per species ≈ 60

Emotions experienced during the time of interaction with the wood according to software (second by second).

Emotions are brief, variable events. Imotions software was used to capture changes in people's microexpressions during the time they first interacted with samples of each wood (thirty seconds) and report variations in the emotions they experienced.

Uses, applications, finishes and processes

Suggested experiential applications and uses

Based on people's preferences about the options presented, the uses and applications that were most frequently associated with each species from experience and perception were defined, in contrast to what was suggested from technical aspects and specialized literature, which is shown at the beginning of each species card.


Objects
N per species ≈ 60

Public spaces
N per species ≈ 60

Household spaces
N per species ≈ 60

Finishes and processes associated with the species

Based on the options presented, the finishes and production processes that people suggest most frequently for each species from their experience and perception were defined, in contrast to what was established from technical parameters, defined at the beginning of each species sheet.


Finishes
N per species ≈ 60

Processes
N per species ≈ 60

Bibliographic references *

Catalán L., J., Vásquez V., L., Hernández C., G., et al (2020). Tensiones admisibles de la madera aserrada estructural de roble (Nothofagus obliqua (Mirb.) Oerst.) con clasificación visual [Allowable stresses of oak (Nothofagus obliqua (Mirb.) Oerst.) structural sawn timber with visual grading] (pp.14-16). Santiago, Chile: INFOR.

Díaz-Vaz O., J., Devlieger Sollier, F., Juacida Percaz, L., et al (1986). Maderas comerciales de Chile. Guía de reconocimiento [Commercial woods from Chile. Recognition guide] (p.44). Valdivia, Chile: CONAF : Editorial Alborada

García, N. & Ormazabal, C. (2008) Arboles Nativos de Chile [Native trees from Chile] (p.117). Enersis S.A. Santiago, Chile.

Hernández, G.. & Pinilla, J.C. (2010). Propiedades de la maderas de especies forestales nativas y exóticas de Chile [Properties of the wood of native and exotic forest species from Chile] (p.85). INFOR.

Photographs of foliage and flowers of each species belong to www.chilebosque.cl and their use was authorized by Diego Alarcón under the academic and non-profit context of this project.

The photographs of the different woods were taken by Francisco Rojas Miranda, who was part of the project team.

The circumflex model of emotions used is based on: Scherer, K. R. (2000Emotion. In M. Hewstone & W. Stroebe (Eds.). Introduction to Social Psychology: A European perspective (3rd. ed., pp. 151-191).