The PiCUS tomographs, laptop and sensors laid out in their open carrying cases beside a tree

Training

Internal Tree Inspection Programme

The Internal Tree Inspection Programme (ITIP) provides structured internal tree inspection training in the inspection of the internal condition of trees, combining Visual Tree Assessment with sonic tomography, electrical resistance tomography and microdrilling to support informed and proportionate decision-making.

Introduction

The Internal Tree Inspection Programme (ITIP) is a two-day course designed to raise professional standards in the inspection of the internal condition of trees.

It provides structured arboricultural training for professionals involved in commissioning, carrying out or reviewing internal tree inspections. The course covers the specification of inspections, the role of Visual Tree Assessment (VTA), the use of sonic tomography, electrical resistance tomography and PD400 microdrill techniques used in modern internal tree inspection and tree diagnostics. It also introduces key failure criteria used in the assessment of hollow trees, helping participants apply inspection results within a clear, evidence-based framework for tree risk assessment and management decisions.

A group taking notes in a classroom-style workshop in a wooden room with large windows, with tomogram graphs on a large monitor

Course: Two days
Cost: £595 + VAT

Course Overview

It provides structured professional training for arboricultural professionals involved in commissioning, carrying out or reviewing internal tree inspections.

Combining classroom learning with practical field exercises, the course introduces a structured approach to Visual Tree Assessment (VTA), tomography and microdrill investigation. The course aims to develop thoughtful and confident professionals who understand the inspection equipment, interpret results responsibly, make proportionate evidence-based decisions, and communicate those decisions clearly in professional arboricultural reports.

Course Objectives

Understand the role of Visual Tree Assessment (VTA) in specifying and guiding internal tree inspections
Learn the correct setup and operation of the PiCUS 3 Sonic Tomograph, PiCUS TreeTronic electrical resistance tomograph and the IML RESI-PD400 microdrill
Develop the ability to interpret tomograms and drilling resistance measurement curves to understand the internal condition of trees
Carry out structured field inspections that integrate VTA with internal measurement techniques
Understand key principles relating to hollowness, residual wall thickness, failure criteria and their relevance to tree risk assessment and management decisions

Cost: £595 + VAT

Who should attend?

Arborists with a keen interest in trees
Arboricultural Consultants
Tree Surveyors
Tree Officers
Tree Owners/Managers with some arboricultural knowledge
Arboricultural professionals involved in internal tree inspection, tree diagnostics and tree risk assessments

A man in a grey cap and green jacket carrying out a tree inspection on a large trunk with electronic equipment

Day 1

Specification, VTA and tomography

Day 1 covers the specification of internal tree inspections, the role of Visual Tree Assessment (VTA), and the use of sonic and electrical resistance tomography. Participants take part in field exercises, group research and practical sessions to understand how inspections are specified, how the equipment is used, and the limitations and best practices associated with internal tree inspection, tree diagnostics and advanced tree inspection techniques.

Course participants outdoors using the IML Resi-PD400 microdrill on a tree trunk

Day 2

Microdrilling and failure criteria

Day 2 introduces the IML RESI-PD400 Microdrill, focusing on drilling technique, measurement curve interpretation and the use of failure criteria. The day combines theory with practical application and concludes with a written assessment designed to evaluate candidates’ understanding of the inspection principles, equipment and interpretation methods covered across the two days.

What people have said about our course

‘Knowledgeable & Approachable’

Phil is a knowledgeable and approachable arboriculturist. Despite using the PiCUS for nearly ten years, I learned techniques and features I didn’t even know existed! His clear practical teaching made a real difference to how I now use the equipment.

Matt DTO, Leicester CC

‘Thoroughly Impressed’

I recently completed the Internal Tree Inspection Program and was thoroughly impressed.
Phil was knowledgeable and approachable, and the well-organised materials made the challenging course engaging. I gained a valuable new skill and highly recommend it to anyone in tree care.

D. WealeWestonbirt, The National Arboretum

‘Highly Informative & Especially Valuable’

I recently attended the pilot Internal Tree Inspection Programme and found it highly informative. It boosted my confidence in using and interpreting internal inspection equipment, while highlighting both strengths and limitations.
The supportive, hands-on learning environment made the experience especially valuable.

Douglas WilliamsArboriculturist/Ecologist MSc, MArborA, ACIEEM, MRSB

‘Excellent – Clear, Engaging and Hands-On’

Phil’s first Internal Tree Inspection Program was excellent—clear, engaging, and hands-on. He made technical topics easy to grasp, and I now feel much more confident assessing tree health.

Joe PWestonbirt, The National Arboretum

‘Highly Recommended For Anyone Seeking Reliable Data’

The internal tree inspection program greatly boosted my confidence in using and interpreting sonic tomography and resistance drilling. The engaging delivery kept me involved, and the course covered both equipment use and the critical nuances affecting accuracy. Highly recommended for anyone seeking reliable data.

Mike TuckerDirector, Arb Tree Works Ltd

‘Highly Valuable & Highly Recommended’

As a Level 4 Tree Life student, I found the course highly valuable. Practical application of theory, excellent equipment, and knowledgeable instruction boosted my confidence—especially in data interpretation, which directly supports my work as a tree officer. Highly recommended.

J. TysonL4 Student and Tree Officer

‘Hugely Beneficial and Would Strongly Recommend’

This is a hugely beneficial course for Tree Officers, Consultants, and Contractors who use, are considering using, or are involved with analysing the data of the equipment, and I would strongly recommend it.

JustinTO, Cotswolds DC, BSc (Hons), MArborA, TechArborA

‘A Game-Changer’

Phil’s inaugural Internal Tree Inspection Program was a game-changer for our team. His knowledge, passion, and hands-on approach made the sessions both informative and engaging.
We walked away with a deeper understanding of tree health and structural assessment, and the confidence to apply what we learned in the field.

Billy DWestonbirt, The National Arboretum

‘Relaxed, Practical and Packed with Useful Info’

Phil nailed the first Internal Tree Inspection Program—relaxed, practical, and packed with useful info.
His passion made it engaging, and the hands-on learning with real trees made it truly effective.

Chrissie DWestonbirt, The National Arboretum

‘Excellent Course, Well-Structured and Delivered’

Excellent course, well structured and delivered.
It should be considered a must-do for anyone carrying out internal inspections using diagnostic equipment, and essential for anyone considering purchasing the equipment and offering the service.

Nigel DaviesHGSS Tree Officer

Phil taking notes beside a veteran tree in long grass

Register your interest today

Stay informed about upcoming internal tree inspection training dates and secure your place on future courses, or arrange a private course for an internal team.

Training courses are available to arboricultural professionals across the UK. Courses so far have been attended by local authority tree officers, consultants, contractors, students and the team at Westonbirt, The National Arboretum.