iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
LiDAR can measure some vegetation and terrain beneath a forest canopy, but it cannot see continuously through trees. Each laser pulse is intercepted, scattered or reflected by whatever it meets first. Some pulses reach lower branches, shrubs or the ground, allowing a point cloud to model vertical structure. In dense or tall forests, however, far fewer pulses reach those layers, and a low return may be a lower branch rather than understory or bare earth.
The useful question is therefore not “Does LiDAR penetrate trees?” but “Are there enough, well-classified returns at the layer and scale I need?” The answer depends on canopy structure, pulse density, scan geometry, season, sensor type, processing and validation.
How a LiDAR pulse samples a forest
An airborne LiDAR instrument emits laser pulses toward the ground and records the time and strength of returned energy. A single pulse can produce multiple observations when portions of the beam reflect from several surfaces on its path.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Imagine a pulse crossing a forest column. It might first return from a top-leaf cluster, then from a lower branch, then from a shrub and finally from soil. Those returns are points at different elevations. Millions of points can be combined into a canopy-height model, a vertical-density profile or a terrain model.
#1 Best Overall
- Powerful Turbo Fan:CAGIWIRU Electric Air Duster have reached speed up to 130000RPM,Can efficient remove dust and debris.With LED light and Three Adjustable Speed to meet with different cleaning tasks.
- With Attached USB C Fasting Charging cable.Charing 3 hours,Enjoy up to 240 minutes of use on the lowest setting, For third speed can use for 25mins.with four charging options to meet with your needs.
- Wide Application: attached 5 different nozzles,making it suitable for a variety of scenes, such as car,pet, pc, keyboards, and other electronic devices. It also serves for office and home clean duster.
- Handy Design & Portable:Cordless air duster electric nozzle is Light weight and small size, design and comfortable to hold and space saving, convenient to carry around. You can put it in your room or inside the car without taking up space.
- Economical &Reusable: Built durable materials with a long-lasting battery,our CAGIWIRU air duster it's a sustainable alternative to disposable air cans.
This is sampling, not a camera view. The beam does not create a complete cross-section of every tree. Leaves and branches can stop the pulse, weaken the signal or redirect it. The gaps between pulse tracks and the random arrangement of foliage also leave unsampled spaces. A visible point below the canopy proves that energy reached that location; it does not prove that all objects at that height were detected.
What LiDAR can reveal below the canopy
Canopy height and vertical structure
Returns from the upper crown and lower crown can describe how vegetation is distributed with height. Analysts commonly derive a digital surface model from the highest returns and subtract a bare-earth terrain model to estimate canopy height. Height bins or vertical profiles can show whether vegetation is concentrated near the top, spread through several layers or sparse above the ground.
The quality of these products depends on point density, scan geometry, the sensor’s return-recording method and the classification of ground and vegetation points. They are estimates of structure across sampled areas, not a guarantee that every branch or stem appears.
Recommended Free Tools
Understory cover or density as a modeled estimate
When enough pulses reach low vegetation, analysts can estimate understory presence, cover or density. The output may be a proportion of returns in a height band, a probability of understory occurrence or a map of structural classes. It is not automatically a species inventory and should not be interpreted as a count of every shrub or suppressed tree.
Height thresholds need context. A point 2 metres above the terrain could be a shrub, a sapling, a sloping lower branch or an error in the terrain surface. Classification that uses height alone can therefore label lower overstory as understory.
Rank #2
- Screen Cleaner is Your Screen’s New Bestfriend! - EVEO is proud to present a screen cleaner that’s perfectly suited for your TV. Meet your new screen cleaner, computer screen cleaner, laptop cleaner, iPad cleaner, Macbook,tv cleaner or any other electronic device. Our screen cleaner spray and wipe along with the included plush microfiber cloth, easily removes dust, fingerprints & other smudges on the screen’s surface. Clean effectively for a streak-free screen
- Gentle on your Screens - Our screen cleaner spray and wipes is compatible to be used even for the most sensitive LCD, LED, CRT, and OLED screens in proper use. Be at ease knowing that this product is compatible with all the major brands: LG, SONY, Samsung, Sharp, iPad, iPhone, Android screens, Kindle, PC monitors - we’ve got you covered! Can be used as LCD screen cleaner, tv cleaner, smart tv screen cleaner, and more
- Premium Super Soft Plush Microfiber Cloth - Included in this efficient screen cleaning kit. This screen cleaner spray and wipe has our signature plush microfiber cloth specially designed to comply with screens and monitors and leave them streak-free. Has been shown to effectively absorbs stubborn stains, zero streaks, and no fiber shedding. Always use this together with our screen cleaner for the best results
- Easy-to-Use Screen Cleaner Kit + microfiber cleaning cloth - The EVEO Screen Cleaning Kit will easily be your new favorite tool when it comes to taking care of the things you love most, quick and easy solution for a streak-free screen. Simply screw on the sprayer gun on the screen cleaner bottle. Spray the cleaning liquid onto the microfiber cloth, then wipe the screen until desired cleanliness & shine is achieved.
- Quality Screen Care Kit Worth Purchasing - Enjoy a convenient Screen Cleaner anytime, anywhere you need it. Your satisfaction is our top priority. We stand behind the quality of our products and that’s why, you shouldn’t be worrying at all. We manufacture the Best Screen Cleaner. and can be used for laptop cleaning kit, laptop screen cleaner, tv screen cleaner for smart tv. MacBook screen cleaner, monitor cleaner or screen cleaner spray for electronic devices with microfiber cleaning cloth
Bare-earth terrain beneath trees
A digital terrain model (DTM) can be built from returns classified as ground. In open ground, many pulses reach soil and the classification problem is relatively simple. Under a closed canopy, only a fraction of pulses may reach the surface. A reliable DTM is possible where that fraction is sufficient and correctly identified, but a smooth-looking surface can hide interpolation across areas with little direct ground evidence.
Terrain slope, rocks, fallen timber, leaf litter and water add further ambiguity. A ground model should be accompanied by point-density and quality checks, especially where engineering, flood or habitat decisions depend on small elevation differences.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Why dense or tall forests hide lower layers
Overstory density and height
Every leaf and branch above a target layer is another opportunity for interception. Tall overstory creates a longer path through vegetation; dense overstory presents more material across that path. In the 2018 study by Campbell, Dennison, Hudak, Parham and Butler, both overstory density and height were associated with lower predictive power for understory estimates. The relationship is not a universal threshold: forest type, sensor and acquisition settings change the result.
Pulse density
Higher pulse density increases the number of opportunities for some energy to pass through gaps. Natural Resources Canada’s Federal Airborne LiDAR Data Acquisition Guideline states: “Greater pulse densities increase sampling of the forest canopy, increase the likelihood of obtaining ground returns, and increase confidence in identifying ground returns in forested areas, especially in complex environments.”
More points improve sampling probability; they do not remove ambiguity. If a pulse reaches a lower branch, increasing density does not tell you automatically whether that branch is overstory or understory. Nor can added points recover a surface that the acquisition geometry systematically misses.
Rank #3
- 【Large size】：Measuring 800 x 300 mm/ 31. 5×12 inches, which is wider and taller than others. Large mouse pad can perfectly fit your keyboard and mouse of any size, and there is also ample space for peripherals such as phones, tablets, etc.
- 【LED backlight mouse pad】：Blade Hawks RGB mouse pad provides 7 static modes and 7 dynamic modes will give you the options you are looking for. Power-off memory function remembers the last lighting mode you selected. The super glow fiber Chroma will give you a colorful gaming setup that you want.
- 【Anti-slip rubber base】：Made from Natural rubber, this gaming mousepad will firmly grip your desktop, allowing you to enjoy the ultimate precision in the games you are most passionate about. It also comes with a texture that enhances this ability even further.
- 【Smooth and waterproof surface】: Micro-textured cloth surface, for extremely precise mouse control and a smooth movement. When liquid splashes on the gaming mouse pad, it forms water droplets and slides down. Will not delay your work or gameplay.
- 【Plug and play】: This mouse and keyboard pad is powered by USB, plug and play, no driver required. One button control light modes. Press one time to change the lighting mode, press twice to change the brightness, press and hold about 3 seconds turn ON/OFF.
Scan angle and footprint
Oblique shots travel through more vegetation than near-nadir shots and can increase occlusion on one side of a crown. Natural Resources Canada recommends a scan angle of 20 degrees or less off nadir, with up to 25 degrees as an upper allowance in its guidance. Narrower angles generally improve canopy penetration and support smaller footprints. The appropriate value still depends on terrain, aircraft operations and the required product.
Season and leaf condition
Leaf-off acquisition can reduce interference from deciduous foliage and improve the chance of ground returns. Leaf-on data may be preferable when the goal is to characterize live canopy or seasonal understory. A leaf-off flight does not make every forest transparent: evergreen foliage, branches, terrain and acquisition density continue to control what is observed.
Understory metrics: why the denominator matters
Relative point density is often calculated by comparing points in an understory height range with points in a broader set of returns. The choice of denominator changes the meaning of the metric. A denominator that includes the entire cloud can vary with canopy interception, flight conditions and terrain even when the understory itself is unchanged.
Campbell and co-authors’ 2018 analysis reported that normalized relative point density was a better understory-density metric than overall relative point density in its study setting. The reported model fit was R² = 0.44 for the normalized metric versus R² = 0.14 for the overall metric. Those values describe that study’s sites, variables and validation data; they are not performance guarantees for another forest or sensor.
Normalization can make comparisons more meaningful by accounting for differences in available returns, but it does not solve classification errors or missing observations. A sound workflow reports the metric definition, height limits, normalization method, point-density distribution and reference measurements.
Free tools Windows power users keep installed
One-click scans. No signup required.
Rank #4
- 【Softer and More Comfortable】Vaydeer wrist rest has unique diamond pattern, which is the combination of softness and aesthetics. The materials of wrist rest are improved into higher quality memory foam and covered with silky smooth lycra. The computer wrist rest makes you as comfortable and cushiony as like rest your wrists on clouds.
- 【Ergonomic Wrist Saver】The wrist rests for keyboard and mouse comes with a 17.32×3.15×0.83 inch keyboard wrist pad and a 5.94×3.15×0.83 inch mouse wrist support. Based on ergonomic design, the unique concave shape is the perfect fit for your wrist joints. The wrist rest pad fits most computer keyboards and laptops, improve hand and wrist posture, release your wrist and arm stress.
- 【Non-Slip Rubber Bottom】Featuring an anti-skid silicone base on the bottom, this wrist keyboard support stays firmly in place on your desk, preventing the padding from sliding around, ensuring stable and consistent wrist support during extended computer sessions.
- 【Better Experience & Pain Relief】Our keyboard arm rest is beneficial to alleviate the soreness caused by direct contact and friction between your arm and a hard desk surface, reducing the risk of wrist fatigue or carpal tunnel. The soft texture of memory foam can evenly distribute the pressure around your wrists and provide good support with just enough give.
- 【Helpful in Multiple Scenarios】Whether you're working, studying, writing, typing, gaming, this keyboard and mouse rest combo is an essential accessory to add comfort and support to your hands and wrists. It’s also a great gift for men, women, family, friend, coworker, gamer, teacher, etc.
Ground returns and understory returns are easy to confuse
A lower return is not self-identifying. A branch in the lower crown, a shrub, a fallen log and soil may all occupy overlapping height ranges. Terrain errors can shift a point into or out of an understory band. On sloping ground, a fixed height-above-sea-level threshold is especially misleading; height should normally be normalized to a validated terrain surface.
Analysts use additional evidence such as return order, intensity or waveform shape, local continuity, crown geometry and neighboring points. No single attribute is decisive in every forest. Field plots, photographs or independent observations are needed when the map will support a high-consequence decision.
Airborne and terrestrial LiDAR do not sample the same way
Platform and return technology determine which layers are sampled most effectively. A comparative assessment of full-waveform airborne, discrete-return airborne and discrete-return terrestrial scanning found that airborne systems detected understory in the studied sites, with full-waveform airborne data performing more accurately than discrete airborne data there. Terrestrial scanning provided more detail in lower vegetation near the scanner, while airborne configurations sampled upper strata more effectively. These are comparative findings for the examined sites and settings, not a universal ranking.
| Configuration | Strengths | Typical limitations beneath canopy | Best matched deliverables |
|---|---|---|---|
| Airborne discrete-return | Efficient coverage over large areas; useful for canopy and terrain mapping. | Records selected returns rather than the complete backscattered signal; lower-layer sampling can be sparse in dense forest. | Regional canopy height and terrain models, with understory estimates when density and classification are adequate. |
| Airborne full-waveform | Retains the shape of returned energy, providing more information about vertically distributed targets. | Still subject to occlusion, footprint size, flight geometry and processing assumptions. | Vertical profiles and understory analysis where waveform data and suitable models are available. |
| Terrestrial discrete-return | High local detail in shrubs, stems and lower layers close to scanner positions. | Occlusion behind trunks and foliage; limited area and visibility from each station; registration and plot placement matter. | Detailed plot-scale structure and lower-stratum measurements. |
Combining airborne and terrestrial observations can cover complementary scales, but the datasets must be co-registered and their sampling biases documented.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Fix the driver behind crashes, sound loss and screen glitches3Clear out junk files and repair common Windows errorsHow to plan a forest LiDAR survey
- Define the target layer and product. State whether you need a bare-earth DTM, canopy height, understory cover, suppressed-tree presence, biomass input or a detailed vertical profile. Each target has different density and validation needs.
- Describe the forest and terrain. Record dominant species or forest type, expected canopy height, canopy closure, deciduous versus evergreen cover, slope, terrain roughness and the size of gaps. Required pulse density generally rises as forest and terrain complexity increase.
- Choose platform and return capture. Use airborne coverage for broad areas and upper-canopy structure; use terrestrial scanning when plot-scale lower vegetation is the priority. Consider full-waveform recording when vertical signal shape is important and the processing chain supports it.
- Set acquisition geometry. Keep scan angles near nadir where practical. Natural Resources Canada’s forest guidance recommends 50% swath overlap, with 20% as a minimum, and says specifications should be tailored to terrain, forest complexity, products and scale.
- Choose season deliberately. Leaf-off conditions can help ground mapping in deciduous stands; leaf-on conditions may better represent live canopy and seasonal understory. Document the state of foliage at acquisition.
- Specify density and coverage checks. Require delivered point-density statistics by tile and, where possible, by height band. A nominal average can conceal large gaps under crowns or at swath edges.
- Design validation before flying. Collect field plots or independent reference observations that match the intended output. For understory, record the height range, cover or presence definition and the date of observation so the comparison is meaningful.
- Test a representative subset. Process sample areas containing dense and open canopy, steep and flat terrain, and different forest types. Revise settings before committing to the full survey if lower-layer returns or ground classifications are inadequate.
How accurate can a beneath-canopy result be?
Accuracy is product- and site-specific. A 2009 NERC Open Research Archive case study mapping deciduous woodland from leaf-on and leaf-off airborne LiDAR reported 72% correspondence with field data for presence or absence of suppressed trees and shrubs. It mapped 39.4 hectares, or 26% of that study site, as understory. These figures describe that case study’s forest, mapping method and reference data; they are not general accuracy rates for all LiDAR surveys.
Best Value
- 【No Drill Mounted】Cable management tray can be assembled in as little as 3 minutes or less-simply. Side clips easily clampe the edge of desk, pass through the holes on the sides, and secure excess cables with baskets. Desk cable management supports inward or outward installation to meet your needs in different scenarios, and provides you with great convenience when collecting and organizing wires.
- 【Rubber Pad Protects Desk】Wire organizer under desk built-in soft rubber pads on the clamp protect your desk from scratches, so you will not damage your furniture or office.
- 【Sturdy and Beautiful】Cord management under desk is made of high-quality carbon steel and holds about 15 lbs. The wire basket has 2 holes on each side of the tray to enable your cables to pass freely. Cable baskets are suitable for desk thickness use from 0.4" to 2.4".
- 【Space Saving & Keep Organized】Desk cable management tray holds all your power cords, outlet strips, USB hubs and computer transformers hidden from your feet, and the data cables will not enter the vacuum cleaner to keep your desk clean and tidy. Desk wire organizer is also suitable for use in the kitchen and outdoors.
- 【Reduce Safety Risks】Cable tray under desk keeps all plugs away from your kids, no more worry about tripping. Using 2 holes wire tray saves extra space, helps you easily cabling and wire protection. The mesh design is not easy to accumulate dust, but avoids safety accidents caused by messy wires.
When evaluating a delivered map, ask for confusion matrices or error rates by class, not only a single overall percentage. Also request the number of field plots, their spatial distribution, the season of reference collection, the minimum mapping unit and whether validation areas were independent from training areas.
Common failure modes and practical fixes
“The DTM has large smooth patches under trees.”
Those patches may be interpolated across areas with few ground returns. Inspect ground-point density and scan-angle coverage, compare elevations with field or survey control and flag areas below the project’s minimum evidence threshold. A denser or better-designed acquisition may be required.
“The understory map shows shrubs everywhere lower branches occur.”
Height-only classification is the likely cause. Normalize heights to terrain, add crown and neighborhood rules, and validate against plots that distinguish shrubs from low overstory. Report uncertain or mixed classes instead of forcing every point into a binary label.
“A high point count still produces poor understory estimates.”
Check where the points are located. Density concentrated in the upper crown does not equal density in the understory band. Review pulse density by height, footprint, scan angle, swath-edge coverage and the forest’s vertical structure. More points cannot compensate for a metric or classification method that is mismatched to the target.
“A dataset collected for another mapping job is being reused for inventory.”
Do not assume fitness for purpose. USDA Forest Service-indexed work by Borgogno Mondino and colleagues (2020) notes that random and systematic errors can affect point clouds, particularly when the data were not designed for forestry. Verify acquisition specifications, processing history and independent validation before deriving inventory variables.
A decision rule for interpreting “penetration” claims
- For broad terrain mapping: ask whether enough classified ground returns exist in the forest type and terrain, and whether density and interpolation diagnostics are supplied.
- For canopy height: confirm that the upper surface and terrain reference were generated consistently and that gaps or saturation are documented.
- For understory structure: require height-normalized metrics, a stated classification method and reference plots; do not accept a simple “points below X metres” rule without qualification.
- For individual trees or shrubs: treat detection as probabilistic. Occlusion and overlapping height ranges mean that absence of a return is not proof of absence.
- For engineering or regulatory decisions: use a survey designed for that decision, with independent checks at the scale of the required accuracy.
LiDAR can reveal a forest’s lower layers when the acquisition samples them and the processing distinguishes them responsibly. It cannot provide a continuous, unambiguous view through every canopy, and a dataset’s usefulness must be judged against the specific layer, scale and decision it is meant to support.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →
