## 1 Introduction
For any given location, all multi-directional data channels are acquired within less than seven minutes [40; 41]. Studies based on MISR data have shown that using multi-angular observations improves the estimation of canopy structural parameters [40; 42; 43]. For instance, [PERSON] [44] reported that tree cover and height could be retrieved more effectively from MISR surface BRF data in Finland's Fennoscandia tundra-taiga transition zone. At the 1.1 km spatial resolution, the relative root mean square error (rRMSE) for tree height and tree cover were 35.4% and 49.2% when using the spectral bands from the nadir camera only, and dropped to 25.4% and 36.9%, respectively, when using the spectral bands from all 9 cameras. Further, theoretical and applied studies haveestablished that synthetic parameters describing reflectance anisotropy of land surfaces can also be used successfully to characterise the structural properties of vegetation [41; 42; 45]. One such model is the Rahman-Pinty-Verstraete (RPV) model, which describes the BRF of a surface using a combination of three parameters \(\rho_{0}\), \(k\), and \(\Theta\)[41; 45; 46; 47]. The \(\rho_{0}\) parameter is a measure of the mean spectral brightness of the target [26; 48; 49; 50]. The \(k\) parameter controls whether the reflectance anisotropy exhibits the usual bowl-shaped (\(k<1\)), or a bell-shaped (\(k>1\)) pattern, which has been associated with heterogeneous canopy conditions [41; 47] and the \(\Theta\) parameter captures the degree of forward or backward scattering [51]. Previous investigations suggested that multi-angular reflectance measurements may lead to an improved characterization and monitoring of vegetation structural properties [26; 48; 49; 52]. The MISR instrument is designed to acquire observations with an across-track sampling distance of 250 m at nadir and 275 m in all off-nadir cameras. However, due to the downlink restriction only 12 of the 36 data channels are transmitted at full spatial resolution in the default Global Mode: The four spectral bands of the nadir camera and the red spectral band in each of the other eight cameras. The raw measurements in the remaining 24 data channels are spatially averaged on-board the platform to yield an effective 1.1 km pixel size. As a result, all MISR NASA-generated land surface products are delivered at this spatial resolution, and most MISR-based studies have relied on 1.1 km or coarser datasets. This is an important limitation in Southern Africa where forested landscapes are occupied by heterogeneous savannas dominated by a grass layer and variable (20-70%) woody cover, or consist of remnants of indigenous forests or stands of commercial plantation forests of variable but generally small stand sizes. At the landscape scale, structural patterns along catenae vary over distances between 100 and 300 m in savannas. Recently, however, the MISR High-Resolution (HR) processing system was developed to reconstruct the original spectral observations at their full spatial resolution (275 m) in all 36 data channels [53]. In addition, that system generates a suite of biogeophysical products--e.g., the RPV model parameters, the Leaf Area Index (LAI), or the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), among others--at that same resolution [53]. We hypothesized that the newly processed high resolution MISR MSMD data at 275 m spatial resolution across all the spectral bands should yield improved canopy structural parameter estimates, compared to traditional nadir-pointing instruments [37; 38; 44; 54]. [PERSON] et al. [41] showed that the capacity to characterize the anisotropy degrades rapidly with the spatial resolution beyond 1 km, where all surfaces appear to be the same \"bowl-shape\". Hence, there is a great incentive in documenting the performance of anisotropic data at finer spatial resolution [26; 41; 55].