## 2 Conceptualizing Forest Land Use as a Disturbance Regime
### Challenges for Characterizing Anthropogenic Disturbance Regimes  
Disturbance regimes are conventionally described using measures of ecological change for a given location and period of time. The measures that are often quantified are disturbance:  
* extent
* severity
* persistence
* intensity
* frequency
* and seasonality. However, characterizing forest land use using conventional measures of disturbance regimes is exceptionally challenging. For example, what is analogous to extent and frequency for a disturbance regime that expands, disturbs, and displaces in perpetuity (e.g., exurban development and land conversion)? Many of the conventional measures of disturbance regimes do not adequately capture the impacts of anthropogenic disturbance, thus, new perspectives on anthropogenic disturbance regimes are necessary for understanding forest land use change during the Anthropocene. Extent is an important measure of disturbance for assessing the direct ecological influence of a disturbance, but it is inadequate for capturing non-discrete, linear disturbances. Using extent as an indicator of anthropogenic influence would severely underestimate the ecological impacts of anthropogenic disturbance and make it appear as though the influence is less or smaller than the change that the ecosystem actually undergoes. In such cases, gradient or surface metrics would be preferred to extent for assessing the influence of disturbance, especially related to resource utilization in forests. Despite the limited availability of appropriate metrics to characterize extent, edge density is a standard metric used to estimate extent related to linear disturbances (e.g., km\(\cdot\)km\({}^{-2}\)) and is useful for making comparisons between landscapes or regions [18]. Severity and intensity describe the physical change to ecosystem structure and the energy released during the process of disturbance, respectively [19]. These measures have little quantitative value for energy development because most activities are high-magnitude disturbances that tend to remove most aboveground biomass. The physical changes to ecosystem structure often do not include measures of the loss of ecological memory like stored seeds and buds in the soil profile, but these elements have important ramifications for the future structure of the ecosystem, water penetration, the ability of the soil to store carbon, and site productivity. Persistence describes the length of time the vegetation condition remains disturbed and is an important indicator of permanence. Anthropogenic disturbances are often characterized by high persistence, especially those related to energy resource development and linear corridors. Oil and gas activity often persists in the form of active well sites, pumping stations, and pipelines (Figure 1). Most linear corridors that are cleared in forests become _de facto_ permanent access networks due to continued disturbance and repeated use by human activities [20]. As understood in the context of anthropogenic disturbance, persistence represents human control over successional accumulation of biomass and is a significant component of anthropogenic disturbance regimes [21]. Forest harvesting occurs in such a manner as to promote the regrowth of trees at regular intervals, while linear corridors are maintained as right-of-ways for access purposes and energy development indefinitely constrains successional pathways. Quantifying persistence in anthropogenic disturbance regimes will be a requisite for successfully understanding ecosystem dynamics of forests. Frequency quantifies the interval between successive disturbances at the same location. For most historical disturbance regimes, frequency is often inversely related to magnitude (_i.e._, severity and intensity), but anthropogenic disturbances related to energy development tend to be both frequent and high magnitude. Many land uses in forests are now related to energy extraction and these areas tend to undergo near-permanent land conversion to an un-forested state for an indefinite period of time.