Ingrowth model for pyrenean oak stands in north-western Spain using continuous forest inventory data

Abstract

In this paper, a two stage ingrowth model is presented for predicting periodic, 10 years ingrowth for pyrenean oak (Quercus pyrenaica Willd.) grown in medium to fully stocked coppice stands in north-western Spain. Data from the Spanish National Forest Inventory was used to develop the model, extracting the information from two inventories taken in 222 permanent plots. The first stage of the model predicts the probability of ingrowth occurrence, and in the second stage, the number of recruits is predicted using a conditional model. Both models were biologically realistic and presented logical behaviour. The ingrowth occurrence probability model was dependent on quadratic mean diameter and average height. The recruitment quantification model included stand density and average diameter as explanatory variables. Although the occurrence probability of ingrowth was predicted correctly in 71.7% of cases, the predictions of the number of recruitment are poorer, yielding a coefficient of determination of 0.358. The evaluation criteria included qualitative and quantitative examinations and a testing with independent data from another region. The proposed ingrowth model is the first to be developed for mediterranean oak species in Spain and is an essential feature in any stand growth system.

Two-stage ingrowth models for four major tree species in Alberta

“…On the other hand, if only observations with ingrowth presence were used for model development, ingrowth would be overestimated. The two-stage modelling approach used in this study was considered more suitable (Vanclay 1992;Adame et al 2010;Klopcic et al 2012).…”

“…The second variant has been more commonly used for ingrowth modelling (Vanclay 1992;Qin 1998;Muhairwe 2003;Lexerød and Eid 2005;Adame et al 2010).…”

“…The establishment, growth and survival of regeneration are largely dependent on stand and site conditions, and ingrowth is the final result of these processes. For complex and/or heterogeneous stand structures or long-term predictions, ingrowth must be taken into consideration in growth simulations because of the high probability of ingrowth as a result of different regeneration processes (Lexerød and Eid 2005;Adame et al 2010). Together with other stand characteristics, ingrowth is an essential component of long-term management and yield forecasting of forest stands (Moser 1972;Shifley et al 1993;Vanclay 1994;Klopcic et al 2012).…”

“…Different approaches have been used for ingrowth modelling. Some models estimated ingrowth with single equations, such as linear (Vanclay 1989;Trasobares et al 2004) and nonlinear models (Moser 1972;Hann 1980), some used a two-stage approach through a combination of logistic and linear or log-linear models (Lexerød and Eid 2005;Adame et al 2010), while others used zero-inflated models (Fortin and DeBlois 2007;Li et al 2011). Two variants of the twostage approach are available: (1) predicts the amount of ingrowth through a linear or nonlinear model and then uses logistic regression to distribute the predicted amount of ingrowth among species present in a stand (Vanclay 1989) Communicated by Arne Nothdurft.…”

Growth and yield models in Spain: Historical overview, Contemporary Examples and perspectives

“…In Spain there are just a few exceptions that include an ingrowth submodel in growth and yield models. Two-step ingrowth models for maritime pine (Sánchez-Orois and Rodríguez-Soalleiro, 2002), Scots pine and Mediterranean maritime pine in Central Spain and Quercus pyrenaica (Adame et al, 2010b) have been developed. They include a logistic model to predict the probability of ingrowth occurrence in a specific stand and a linear model for quantifying ingrowth in terms of basal area (m 2 /ha) or number of stems per ha.…”