Author Archives: TimsStruppis

VPPS-SS14-W09-1-TimsStruppis

  • How has the DEM (digital elevation model) been derived from the LiDAR dataset?

Canopy and ground DEMs were produced from LiDAR data sets using a linear interpolation technique.

  • How has the tree height/DSM (digital surface model) information been retrieved from the LiDAR dataset?

It has been retrieved in a three-step-process:

1. The ground (DEM ?) is subtracted from the first return LiDAR DEM in order to yield forrest height surface

2. The LiDAR return of the peaks of tree crowns is detected, gathering that peaks represent indivitudal crowns .

3. Data for indivitudal trees of plot is extracted (using information about location of individual trees ?).

  •  How has the vertical structure been classified into single- and multi-story areas?

Trees < 1.54 m were classified single story, trees > 1.54 are classified multistory, based on the median values of tree heights variance observed in plots.

  • What is the principle difference between the single-/multi-storage data set and the characterization of the forest areas using the coefficient of variation approach (section 4)?

The single-/multistorage dataset, classifies a forrest in only two classes single or multistorage. The CV does not characterize forrest by classes but calculates a unitless ratio between the standard deviation and mean of tree heights. It it thus independent of sample size and can be used to compare samples of unequal sizes.

  • Which errors of the approach can be attributed to post spacing?

Tree heights measurements can be incorrect and therefore influence tree heights variances: inflate single-story tree heights variance and reduce multi-story tree heights variance.

 

VPPS-SS14-W08-1-TimsStruppis

Landscape: A Landscape is defined by a constellation of patches which are chosen under consideration of ones interest.

Patch: A Patch is also dependent on ones interest, it can be defined in different scales, it`s boundaries are not naturally given.

Matrix: The matrix is the biggest patch that can be sensibly defined for the object of interest, it sets the frame within which the research takes place.

Scale: The scale sets the extent and the grain (the extent of the smallest defined entity) of observation.

Landscape context: The Landscape context is the sourroundings of a defined landscape, these sourroundings can be very important especially if extent-grain-ratio is low.

Landscape structure: Landscape structure means that every landscape is determined by composition and configuration, which can influence (in combination or not) ecological processes and organismus.
Landscape composition: Landscape composition subsumes the variety and plentys of patch types, which are realized within a landscape, but it does not provide information about the spatial situation inside the landscape mosaic.

Landscape configuration: Landscape configuration depicts the physical arangement or spatial character of patches. Two types of measures can be distunguished: Measures of the spatial property of different patches. Models of ecological processes that include landscape configuration.
Landscape metrics: Landscape metrics are referred to as “stepping-stane modells”. These metrics measure the voriability in patch characteristics, exploring the relationship between surrounding patches and providing an average patch characteristic which allows conclusions e.g. about the suitability of the landscape fpr certain species.