SAF Certified Forester (CF) · USA · Society of American Foresters
Original practice questions written to the published syllabus · not past papersSpatial data and analysis for forest management: GIS data models, spatial analysis, GNSS, airborne and terrestrial LiDAR, and the digital tools of precision forestry. General remote sensing and GIS for land and water is in the Agricultural Engineering track (remote-sensing-gis).
In the exams: ICAR AICE-JRF 59 Unit 4 (GIS and remote sensing concept and scope); GISP and ASPRS certifications; growing share of SAF and FPBC professional practice
How our questions for SAF Certified Forester spread across the units of Forest GIS, GNSS & LiDAR Analytics. Difficulty: 3 easy, 9 medium, 6 hard.
| Forest stand and compartment databases | 4 | |
| Spatial decision support and multi-criteria analysis | 3 | |
| Spatial analysis: overlay, buffer, terrain analysis | 2 | |
| GNSS data collection and accuracy | 2 | |
| Area-based and individual-tree LiDAR inventory | 2 | |
| Terrestrial and mobile laser scanning | 2 | |
| GIS concepts: vector and raster data, projections, datums | 1 | |
| Open data and cloud platforms for forest monitoring | 1 | |
| Map production and cartographic standards | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Two layers of the same forest are overlaid and the roads are offset by about 150 m in a consistent direction. The most likely cause is:
C. The layers use different datums with no transformation applied
A consistent shift of tens to hundreds of metres is typical of a datum mismatch. Scale differences cause irregular, not uniform, offsets; attribute keys do not move geometry.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Before deriving a stream network from a DEM, small depressions are filled. Why?
A. Spurious sinks would stop flow and break the network
Artificial pits trap flow, so accumulation stops and streams are fragmented. Filling does not remove vegetation or change a DSM into a DTM.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Which field practice most improves GNSS plot-centre accuracy under dense canopy?
D. Logging many fixes with an antenna raised on a pole
Averaging many fixes and raising the antenna above understorey reduce error. Using fewer constellations reduces visible satellites; a zero mask admits low, noisy signals.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Which trees are most often missed by individual-tree detection from airborne LiDAR?
C. Suppressed and understorey trees
Lower trees hidden under the upper canopy cause omission errors; tall, distinct crowns are detected best.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Why do adjacency (green-up) constraints make harvest scheduling much harder to solve?
A. They link decisions on neighbouring stands into integer choices
Adjacency rules turn the problem into a large integer programme in which each stand's decision depends on its neighbours; heuristics such as simulated annealing or tabu search are often used.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Why should red and green not be the only contrast distinguishing two categories on a field map?
A. Common colour-vision deficiencies make them hard to tell apart
Red–green colour deficiency is common, especially among men; adding differences in lightness, pattern or symbol shape keeps the map readable.
Further reading: Longley P; Bolstad P; Wulder M; Maltamo M
Ten here, 18 in the app. The Laisha app has every practice question we have written to SAF Certified Forester in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.
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