Topic Introduction

In this topic, we will introduce the definition, types, design, validation, and applications of ecological models. We will cover both empirical models and process-based models but only focused on the latter in this topic as the former will be introduced in more detail in later modules. 

By the end of this topic, you should be able to:

• Describe the definition of ecological models;
• Distinguish an empirical model from a process-based model;
• Describe the advantages of an empirical model over a process-based model and vice versa;
• Describe the roles of ecological models in helping the management of forest resources under climate change;
• List 2-4 major process-based models.

Topic Readings

Required Readings

• None

Optional Readings

• Buck-Sorlin G. (2013) Process-based Model. In: Dubitzky W., Wolkenhauer O., Cho KH., Yokota H. (eds) Encyclopedia of Systems Biology. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-9863-7_1545 Links to an external site..
• Mitchell KJ (1975) Dynamics and simulated yield of Douglas fir Links to an external site.. For Sci Monogr 17:39

Fundamental Concepts

Self Check (For certificate learning only)

After reading for this topic, take 5 minutes to take an online self-check quiz for the topic. The main purpose of the quiz is for you to self-check how well you grasp the contents for this topic. It will cover contents of the lecture(s) for the topic. Five attempts are allowed and highest mark will be saved to show your achievement.

When you are ready, click the link Self-check Quiz 2.2 to start taking the quiz.

Activities & Assignments (For certificate learning only)

Online Discussions

Online discussions are much like face-to-face discussions. Students are required preparation and active participation in order to the learning objectives. The online discussion will be asynchronous (i.e., students can participate at different times) and will be closed at the end of the week. This discussion accounts for 2 marks graded based on participation and quality of the posts. Each student is required to have at least one post. Everyone is encouraged to rate each post. The first post account for 70%, the second one for 20% and third one for 10% of the participation, respectively. The first post with at least five sentences is considered as the “first post”. A simply “Yes or No” post is not considered as a post. The quality is graded by both Instructor (50%) and peer rating (50%). 

Discussion Topics:

1. What are the significance of ecological models.
2. Pros and cons of process-based models.

To participate in the discussion, please go to Online Discussion 2.2 class forum.

Graded Assignments

Module 2 Test

Module 2 Test Due at 23:59pm on Day 7 of this week (PST). See Course Schedule for specific due date. 

Topic Summary

There are two types of ecological models, analytical models and simulation models. Analytical models are called empirical models or correlative models. They are built based on direct relationships derived from field observations, and often relatively simple. Simulation models, on the other hand, are to simulate the detail physical or physiological processes. Simulation models are also called numerical models or process-based models. Most widely used process-based models in forestry include 3-PG, FORECAST, Tree and Stand Simulator (TASS), and LANDIS.

Topic Self-review (For self learning)

Please use the reflection questions below as study guide to conduct self-review for the topic:

1. Why do we need to build ecological models?
2. What are the two types of ecological models?
3. Why do we need to validate an ecological model?
4. Is a more sophisticated model more accurate?
5. Which model will suite your objective better?